Stephen Harriman Long
Representation of the 1819 oil painting of Major Long. Portrait painted by Charles Willson Peale
Born	(1784-12-30)December 30, 1784 Hopkinton, New Hampshire, U.S.
Died	September 4, 1864(1864-09-04) (aged 79) Alton, Illinois, U.S.
Education	Dartmouth College
Spouse	Martha Hodgkins
Parent(s)	Moses and Lucy (Harriman) Long
Engineering career
Discipline	Civil Engineer, Topographical engineer, explorer, inventor.
Institutions	US Army Corps of Engineers (1814-38), United States Army Corps of Topographical Engineers (1838-63).
Employer(s)	Baltimore and Ohio Railroad, Western & Atlantic Railroad.
Projects	Federal expeditions in the trans-Mississippi West (1817–1823); federal internal-improvements surveys (1824–early 1830s); early railroad route studies and engineering.
Significant design	The Long truss

Stephen Harriman Long (December 30, 1784 – September 4, 1864) was a United States Army officer, topographical engineer, civil engineer, and inventor whose career combined military engineering, scientific exploration, federal internal improvements, and early railroad and bridge development.^[1][2]

He is best known for leading federal exploratory expeditions in the trans-Mississippi West between 1817 and 1823, including the 1820 reconnaissance of the Great Plains that contributed to the contemporary characterization of portions of the region as the “Great Desert.”^[1][3]

From the mid-1820s onward, Long played a significant role in federally authorized surveys under the General Survey Act and in early railroad development, including work associated with the Baltimore and Ohio Railroad and the Western & Atlantic Railroad.^[1][4]

In 1830, he patented the Long truss, an early timber bridge system that incorporated adjustable compression bracing and deliberate proportioning of members according to calculated stresses, a design later identified by historians as an early application of analytical principles in American bridge engineering.^[5][6]

Stephen Harriman Long was born on December 30, 1784, in Hopkinton, New Hampshire, to Moses Long (1760–1848) and Lucy (Harriman) Long (1764–1837).^[1]: 27 He was the third of thirteen children, in a family of eight sons and five daughters.^[1]: 29

Several of his siblings pursued professional careers. His brother Moses Long became a physician; Enoch Long entered the printing trade; and George Washington Long (1800–1880) graduated from the United States Military Academy, served as an artillery officer, and later undertook topographical duties.^[1]: 29 A cousin, Horace Childs, later acted as an agent in connection with Long’s bridge patents.^[1]: 29

In 1819, Long married Martha Hodgkins (1799–1873) in Philadelphia.^[1]: 72 The couple had six children. Martha Hodgkins was the sister of Isabella Hodgkins Norvell (1804–1873), who later became the third wife of U.S. Senator John Norvell.^[1]: 72

Long entered Dartmouth College in 1805 and received the A.B. degree in 1809.^{[1]: 30–34} He was awarded the A.M. degree in 1812.^{[1]: 30–34}

At Dartmouth, he received instruction in mathematics, natural philosophy, and surveying—subjects that formed the standard scientific curriculum of the period and later proved directly applicable to his work in military engineering and exploration.^{[1]: 30–34}

After graduation, Long taught school in New Hampshire and later in Germantown, Pennsylvania.^{[1]: 34–36} During this period he developed practical mechanical skills and constructed hydraulic machinery that attracted the attention of Joseph Gardner Swift, then Chief Engineer of the United States Army and superintendent of the United States Military Academy.^{[1]: 36–38} Swift first employed Long as a civilian assistant on projects connected with the improvement of the harbor defenses of New York Harbor.^{[1]: 36–38} In 1814, at Swift’s urging, Long accepted a commission as a second lieutenant in the Corps of Engineers.^{[1]: 36–38}

Long was a commissioned officer of the United States Army from 1814 until his retirement in 1863. He served in the Corps of Engineers and, after the 1838 reorganization that created the Corps of Topographical Engineers, in that separate corps until its merger back into the Corps of Engineers in 1863. Much of Long’s work on internal improvements and early railroad surveys was performed on detached duty or through federally authorized engineering boards. During the American Civil War, he remained in Federal service and held the rank of colonel at the time of his retirement.

Long entered the United States Army Corps of Engineers as a second lieutenant in 1814 after prior civilian work involving hydraulic machinery and mechanical devices had attracted the attention of Chief Engineer Joseph Gardner Swift.^{[1]: 36–38}

From 1815 to 1816, Long served as assistant professor of mathematics at the United States Military Academy at West Point, New York.^[1]: 38 This appointment reinforced his grounding in applied mathematics and mechanics at a time when formal engineering education in the United States remained closely tied to military instruction.

Following the postwar reorganization of the Army in 1816, Long received the brevet rank of major and was assigned to topographical duties.^[1]: 38 His early assignments included work connected with the improvement of harbor defenses in New York Harbor, where he gained practical experience in masonry fortification, site preparation, and large-scale construction logistics.^{[1]: 36–43}

Long was subsequently ordered to report to St. Louis in the Army’s western department, where he began organizing instruments, personnel, and survey procedures for reconnaissance work in the Mississippi Valley.^{[1]: 39–43} These assignments marked the beginning of Long’s sustained engagement with topographical surveying and route examination, skills that would shape his later exploratory and internal-improvement work.

Between 1817 and 1823, Long directed a series of federally authorized reconnaissance expeditions in the trans-Mississippi West that combined military route examination with systematic scientific observation.^{[1]: 46–141} Long's expedition was part of a broader sequence of U.S. government-sponsored explorations undertaken after the Louisiana Purchase (1803). Preceding federal expeditions associated with Lewis and Clark, Zebulon Pike, and the Freeman–Custis expedition likewise combined geographic reconnaissance with scientific and military objectives.^[7][8]

In 1817, Long headed a military excursion up the Mississippi River to the Falls of St. Anthony near the confluence with the Minnesota River.^{[1]: 46–47} In recommendations following the trip, he urged the establishment of a permanent post in the region; the Army subsequently established Fort Snelling to secure the Upper Mississippi and protect settlers in the Upper Mississippi Valley.^{[1]: 46–47} Long later published an account of the expedition as Voyage in a Six-Oared Skiff to the Falls of Saint Anthony in 1817 (1860).^[9] During the journey, Long encountered two grandsons of the explorer Jonathan Carver, including Johnathan P. King who were traveling to substantiate Carver’s disputed claim to a large land grant in what is now Wisconsin and Minnesota (“Carver’s grant”); Long recorded that their efforts did not verify the claim.^{[9]: 10, 43, 65 [10]: 50}

In 1818–1819, Long organized and led the scientific component of the Yellowstone Expedition on the Missouri River.^{[1]: 59–84} For this expedition he designed and supervised construction of the steamboat Western Engineer, one of the earliest purpose-built shallow-draft vessels for western river navigation.^[1]: 63 The vessel incorporated mechanical refinements intended to improve efficiency and maneuverability in inland waters.

The 1820 expedition to the Great Plains and toward the Rocky Mountains further demonstrated Long’s emphasis on measured observation and cartographic documentation.^{[1]: 105–131} The published reports included astronomical determinations of longitude and latitude, descriptions of river gradients, soil classifications, and evaluations of transportation routes. Portions of the central plains were described in contemporary publications as part of a “Great Desert,” a designation that reflected both environmental assessment and the expedition’s judgment of the agricultural settlement potential.^[3]

A final northern reconnaissance in 1823 included boundary-related surveys near Pembina, North Dakota and additional mapping in the Upper Mississippi region, including work near Pembina related to boundary determination at the 49th parallel.^{[1]: 133–141} In the same year, Long was elected to the American Philosophical Society.^{[1]: 133–141 [11]} By the end of these expeditions, Long had established himself as one of the Army’s leading practitioner-engineers in applied topographical science, combining field measurement, mechanical ingenuity, and analytical reporting.

These expeditions gave Long an unusually comprehensive understanding of continental-scale geography, river systems, and the structural logic of mountain barriers.^[12] Unlike many contemporary engineers whose experience was confined to localized canal or road projects, Long had traversed vast drainage basins and observed firsthand the constraints imposed by topography. This geographical awareness later informed his engineering judgments regarding route location and grade control.

Beyond the expeditions' scientific collections and geographic data, their officially published narratives proved culturally influential. Long's reports contained some of the earliest widely circulated illustrations of western landscapes and Indigenous peoples and later served as literary inspiration for James Fenimore Cooper’s novel The Prairie (1827).^[12]

Following the conclusion of his western expeditions, Long’s duties shifted toward transportation infrastructure under the General Survey Act of 1824.^{[1]: 143–146} The act authorized the President to employ officers of the United States Army Corps of Engineers to examine routes for roads and canals of national importance. In practice, this program expanded the Army’s role beyond military fortification to systematic evaluation of civil works.

Long participated in surveys intended to connect the Atlantic seaboard with the Ohio River and Mississippi River valleys, as well as examinations of canal routes and river improvements.^{[1]: 145–152} His reports characteristically combined topographic description with engineering analysis of alignment, gradient, water supply, and cost estimation. These assignments required translating field reconnaissance methods into practical construction planning.

Shortly before joining the Baltimore and Ohio surveys, Long revisited the Potomac and Blue Ridge region during a federal investigation of a proposed National Road extension between Washington and Buffalo. In that 1826 reconnaissance, he articulated what became known as his theory of “equated distance,” converting vertical ascent and descent into equivalent horizontal mileage in order to compare alternative routes objectively.^{[12]: 54–55} Long argued that every hill constituted an impediment increasing effective distance and required power, and that routes should therefore privilege river valleys and gradual gradients over direct but mountainous alignments.^[12]

Dilts further observes that this analytical framework—combining topographic reconnaissance, tabulated comparisons of ascents and descents, and systematic evaluation of watercourses, anticipated the formalized reconnaissance-and-survey methodology later standardized in railroad engineering.^{[12]: 56–57}

In 1827, shortly after the chartering of the Baltimore and Ohio Railroad, the company formally requested federal engineering assistance under the General Survey Act of 1824. Secretary of War James Barbour approved the request, and three government surveying parties were assigned to the project.^[13]: 238

One of these parties was headed by Long, who, together with Major William G. McNeill and Dr. William Howard, directed the determination of the railroad’s initial route between 1827 and 1829.^{[13]: 238–239} Hill notes that some fourteen Army engineers were engaged on the Baltimore and Ohio between 1827 and 1830.^[13]: 239

Upon their return from a study tour of British railways in 1829, McNeill and Jonathan Knight served with Long as members of the company’s board of engineers, while Lieutenant George W. Whistler directed early construction operations.^{[13]: 238–239} Long’s association with the B&O ended in 1830 following a disagreement within the company, after which the Army engineers including Long were reassigned to other railroad surveys.^[13]: 239

In Pennsylvania, Long examined alternative routes across the Allegheny Mountains as part of the state’s canal-and-rail system, the Allegheny Portage Railroad. In the jointly transmitted 1831 reports with Moncure Robinson, both engineers recommended a railroad rather than a macadamized highway for the mountain crossing, though they differed in alignment and mechanical treatment of inclined planes.^[14]

Concurrent with his surveying work, Long pursued mechanical experimentation in steam locomotive design. He received patents beginning in 1826 for improvements in locomotive construction and steam-engine efficiency.^{[1]: 159–165} In 1832 he entered into partnership in the American Steam Carriage Company, an effort to commercialize his locomotive concepts. Although the firm dissolved by 1834, the episode demonstrated Long’s engagement with emerging railroad technology beyond route location alone.

In 1837, Long obtained leave from the Army to serve as chief engineer of the Western & Atlantic Railroad in Georgia, a state-sponsored line intended to connect the interior of Georgia with the Tennessee River system.^{[1]: 190–192} Between 1837 and 1840, he conducted the principal location surveys that established the alignment adopted for construction, including determinations of grades, curvature, river crossings, and terminal siting.^{[1]: 192–196}

Long participated in the selection of the railroad’s southern terminus, a location that later developed into the city of Atlanta.^{[1]: 196–198} His work on the Western & Atlantic represented one of the earliest instances in which a state government relied upon a professionally trained Army engineer for comprehensive railroad location and design.^[15]

By 1840, Long’s career had encompassed exploratory reconnaissance, federal infrastructure surveys, locomotive development, and applied railroad engineering, positioning him at the intersection of military engineering and early American industrial transportation.

During his association with early railroad projects in the late 1820s, particularly work connected with the Baltimore and Ohio Railroad, Long turned to the problem of timber bridge construction for railroad use.^{[1]: 155–160} At a time when American long-span bridges were commonly built according to empirically derived proportions, Long developed a patented truss system that incorporated adjustable compression bracing and deliberate proportioning of members according to calculated stresses.

In April 1830, Long received U.S. Patent No. 1,601 for an “Improvement in the Construction of Bridges,” followed by a second patent (No. 1,933) in 1839 that refined the joint configuration and load transfer.^{[16] [17]}

John C. Danko identifies Long as “the first bridge designer to make a substantial attempt at applying scientific principles to the design of the simple truss bridge,” noting that Long employed contemporary statics, including the parallelogram of forces and simple-beam theory, in proportioning truss members.^{[6]: 149, 159} Frank Griggs similarly observes that Long sized individual members according to anticipated stress magnitudes rather than adopting uniform timber dimensions throughout the span.^[5]: 260

The resulting configuration, later known as the Long truss, used slightly overlength diagonal braces, driven into compression by adjustable wedges, creating a prestressed system whose internal force distribution depended on the maintained bearing and joint stiffness.^{[6]: 232–236} Modern reassessments of nineteenth-century timber truss construction have emphasized that the performance of Long’s system relied heavily on joint bearing mechanics and periodic adjustment of wedges to compensate for timber shrinkage.^{[18]: 31–33}

Although the Long truss was used in covered highway bridges and in early railroad applications during the 1830s, increasing locomotive axle loads and the growing availability of wrought iron led to the wider adoption of hybrid timber–iron systems such as the Howe truss in the 1840s.^{[5]: 261–263} Long’s truss work has been cited by later historians as marking a transitional moment in American bridge engineering, between empirically proportioned timber systems and analytically conceived structural design.

In 1837, Congress authorized the construction of a system of United States Marine Hospitals to serve river and coastal seamen.^{[1]: 220–221} Long, then serving in the Corps of Topographical Engineers, was assigned supervisory responsibility for several of the western river installations, including the hospital at Louisville, Kentucky.^{[1]: 220–223} The hospitals were constructed according to plans prepared by architect Robert Mills, while Long oversaw site selection, foundation work, contracts, and construction progress.

Construction in Louisville began in the mid-1840s, following delays due to funding and administrative issues.^{[1]: 221–223} Long subsequently supervised additional marine hospital projects at Paducah, Kentucky; Natchez, Mississippi; and Napoleon, Arkansas.^{[1]: 223–225}

Long was directed in 1849 to supervise construction of the Marine Hospital at Napoleon, Arkansas, located near the confluence of the Arkansas and Mississippi Rivers. After surveying the site, he formally objected to the location on engineering grounds, citing the riverbank's instability and the risk of erosion and flooding.^{[19]: 38–39} Long recommended relocation to a more stable site at Helena, Arkansas, but political considerations prevailed and construction at Napoleon proceeded.^{[19]: 39–40}

Work at Napoleon was repeatedly delayed by flooding, foundation instability, and expiring contracts.^{[19]: 40–41} The hospital was completed in 1854 and opened in 1855.^[19]: 41 During the Civil War, the town was burned in 1862, although the hospital structure survived the conflict.^[19]: 41

Long’s earlier warnings proved prescient. By March 1868, river erosion had advanced to within approximately fifty feet of the building, and within weeks, a portion of the structure collapsed into the Mississippi River.^{[19]: 41–42} The continued encroachment of the river ultimately destroyed the town of Napoleon.

The Marine Hospital at Louisville, Kentucky, which Long supervised but did not design, survives and was later designated a National Historic Landmark.^{[1]: 220–225}

Long retired from the Corps of Engineers in 1863 at the age of 78.^[1]: 267 He died on 4 September 1864, in Alton, Illinois, at the age of 79, and was interred at the Alton cemetery in Alton, Illinois.

Long’s name is commemorated in both geographic features and public historical markers.

• The most prominent feature is Longs Peak in Rocky Mountain National Park, Colorado, first identified during his 1820 expedition and later officially standardized by the U.S. Board on Geographic Names in 1911.^[20][21]
• The city of Longmont, Colorado, founded in 1871, derives its name from Longs Peak; the origin of the place name is documented in a U.S. Geological Survey bulletin on American place names.^[22][23]
• Long’s engineering work is also recognized in state historical marker programs. In Georgia, markers associated with the Western and Atlantic Railroad credit him as chief engineer for the original survey (1837–1840), including the “Zero Mile Post” marker in Atlanta.^[24]
• In New Hampshire, state highway historical markers for Smith Bridge and Blair Bridge reference Long’s patented pre-stressed wooden truss design, the Long truss.^[25][26]
• A Kentucky Historical Marker at the former U.S. Marine Hospital in Louisville, Kentucky recognizes Long’s supervisory role in the hospital’s construction between 1845 and 1852. Designed by architect Robert Mills, the Louisville facility served boatmen on the western waterways during the height of steamboat commerce and became the prototype for seven additional federally funded marine hospitals. Long supervised construction. The building is the only surviving example of an inland U.S. Marine hospital and was designated a National Historic Landmark in 1997.^{[27][1]: 220–225}

• New Hampshire Historical Marker No. 179: Smith Bridge
• New Hampshire Historical Marker No. 196: Blair Bridge

• Goetzmann, William H. Army Exploration in the American West 1803-1863 (Yale University Press, 1959; University of Nebraska Press, 1979)
• Johnston, James Houstoun, Western and Atlantic Railroad of the State of Georgia, Atlanta, 1931
• Kane, Lucile M., Holmquist, June D., and Gilman, Caroly, eds., The Northern Expeditions of Stephen H. Long: The Journals of 1817 and 1823 and Related Documents (Minnesota Historical Society Press, 1978).
• Nichols, Roger L. (2000). "Long, Stephen Harriman". American National Biography (online ed.). Oxford University Press. doi:10.1093/anb/9780198606697.article.2000604.
• Sterling, Keir B., ed. (1997). "Long, Stephen Harriman". Biographical Dictionary of American and Canadian Naturalists and Environmentalists. Greenwood Press.
• White, John H. Jr. (1968). A history of the American locomotive; its development: 1830–1880. New York, NY: Dover Publications. ISBN 0-486-23818-0.
• Nebraska Studies website
• Archived 2009-03-10 at the Wayback Machine
• U.S. Corps of Topographical Engineers - Online Biography of Stephen H. Long

• The Journal of Captain John R. Bell: official journalist for the Stephen H. Long Expedition to the Rocky Mountains (1 folder) is housed in the Department of Special Collections and University Archives at Stanford University Libraries

• Works by Stephen Harriman Long at Project Gutenberg
• PATRICIA JOHANSON - Timeline Biography - 1940-1967 details a 1600 feet (490 m) length minimalist art sculpture 'Stephen Long', installed by Patricia Johanson in 1968 along an abandoned railroad track in Buskirk, upper New York.