U.S. Route 16
US 16 highlighted in red
Route information
Length	489.51 mi[a] (787.79 km) 418.874 mi (674.112 km) in Wyoming[1] 70.64 mi (113.68 km) in South Dakota[2]
Existed	1926[citation needed]–present
Major junctions
West end	US 14 / US 20 at Yellowstone National Park entrance
Major intersections	US 310 / WYO 789 near Greybull, WY US 14A in Cody, WY I-25 / US 87 in Buffalo, WY I-90 / US 14 in Gillette, WY and Moorcroft, WY US 85 in Newcastle, WY US 16 Truck in Rapid City, SD
East end	I-90 / I-190 / US 14 / US 16 Truck in Rapid City, SD
Location
Country	United States
States	Wyoming, South Dakota
Highway system
United States Numbered Highway System List Special Divided
← US 15 US → US 17 ← WYO 14 WY → US 18 ← SD 15 SD → SD 16

U.S. Highway 16 (US 16) is an east–west United States Numbered Highway between Rapid City, South Dakota, and Yellowstone National Park in Wyoming. The highway's eastern terminus is at a junction with Interstate 90 (I-90)/US 14, concurrent with I-190, in Rapid City. The western terminus is the east entrance to Yellowstone National Park, concurrent with US 14 and US 20. US 16 used to extend all the way to Michigan but has been truncated in favor of I-90 and I-96.

US 16 begins at the east entrance to Yellowstone National Park, along with US 14 and the eastern segment of US 20. From the park, the three highways run concurrently to Cody and Greybull. In Greybull, US 14 splits off to the east, while US 16/US 20 heads due south to Basin and Worland. In Worland, US 16 splits off from US 20 and heads east over Powder River Pass on its way to the city of Buffalo. After passing Buffalo, US 16 arches north to the community of Ucross, meeting US 14 again, before arching back south to Gillette. US 16 then runs east concurrently with I-90 between Gillette and Moorcroft before heading southeast to the towns of Upton and Newcastle. The highway then heads east to the South Dakota state line. For most of the way through the state, the highway is a two-lane road. US 16 is 419 miles (674 km) long in Wyoming.^[1]

US 16 is also known as Mount Rushmore Road in western South Dakota. From the state line, the highway travels near Jewel Cave, the fifth longest cave in the world.^[3] The highway goes through the city of Custer and shares alignment with US 385. East of Hill City, US 16 splits off US 385. It then becomes a four-lane divided highway, with the two roadways separated by up to a half-mile (0.80 km) in some places, including the old gold-mining town of Rockerville, which is contained entirely between the two roadways. In Rapid City, a truck bypass runs along Catron Boulevard and Elk Vale Road up to exit 61 on I-90. US 16 is 71 miles (114 km) long in South Dakota.^[2]

The South Dakota section of US 16 is defined at South Dakota Codified Laws § 31-4-138.^[4]

US 16 originally connected Detroit with Yellowstone National Park, including a ferry link across Lake Michigan between Muskegon, Michigan, and Milwaukee, Wisconsin aboard SS Milwaukee Clipper. In Michigan, the route was in use long before automobiles and was known to white settlers as the Grand River Road, and prior to the designation of U.S. Highways in 1926, had been designated as M-16 in the 1920s from Detroit to south of Muskegon. In 1938, reflectorized discs were placed on US 16 every 100 feet (30 m) from Detroit to Lansing, resulting in fewer nighttime traffic accidents. Other states would later do the same on their roads.

US 16 initially crossed the South Dakota–Wyoming state line west of Spearfish. U.S. Highway 216 (US 216) was commissioned in 1930 as a loop off US 16 to the south between Rapid City and Moorcroft, crossing the state line west of Custer. In 1934, US 16 was moved to the US 216 alignment, while the former US 16 became part of an extension of US 14.

In Michigan, most of US 16 was superseded by I-96 and a segment of Grand River Avenue in Detroit ultimately became M-5. US 16 was later decommissioned in Wisconsin, Minnesota, and eastern South Dakota to its present termini.^[5]

Between Rapid City and Dexter, Minnesota, it has been supplanted by I-90. In Faribault County, Minnesota, the highway took on another number as there was already a county highway numbered 16. Residents of the county continued referring to the road as "16" or "old 16" and eventually the county renumbered it as County Road 16 (CR 16). From the county's western border with Martin County, US 16 continued east through the city of Blue Earth as part of 1st Street and Leland Parkway until it briefly combines with US 169/Grove Street. One-half mile (0.80 km) south of that point at the intersection of Grove and 7th streets, CR 16 followed 7th Street and continued east to the border of Freeborn County. Most of the stretch through Faribault County was a relatively narrow two-lane highway with wide gravel shoulders that has been widened at least two times since US 16 was decommissioned. East of Dexter, it is now Minnesota State Highway 16 and State Trunk Highway 16 in Wisconsin. In South Dakota, it was replaced by various state highways (including South Dakota Highway 38, or SD 38, and SD 248) and county roads: generally, in West River, the old alignment was transferred to county responsibility entirely, while, in East River, it remained a state-maintained highway.

An older US 16A in South Dakota has become SD 240.

In South Dakota in 2009, the South Dakota Department of Transportation designated US 16/US 385 between Custer and Hill City, which passes by the Crazy Horse Memorial, now being carved in the Black Hills, as the Crazy Horse Memorial Highway. This segment of US 385 is also a part of the George Hearst Memorial Highway.

Mileage resets at the state line crossing.

State	County	Location	mi[1][2]	km	Exit	Destinations	Notes
Wyoming	Yellowstone National Park		0.000	0.000		East Entrance Road to US 20 west	Continuation into Yellowstone National Park; US 20 resumes in Montana at the park's west entrance (closed winters)
					Yellowstone National Park boundary (East Entrance); fees required
						US 14 begins / US 20 begins / Buffalo Bill Cody Scenic Byway begins	US 14 / US 16 western terminus; western end of US 14 / US 20 / Buffalo Bill Cody Scenic Byway concurrency
	Park	Pahaska Tepee	2.000	3.219	Westbound road closure gate (closed winters)
		Cody	49.410	79.518		WYO 291 south (South Fork Road)
			50.900	81.916		US 14A east / WYO 120 west (16th Street) / Buffalo Bill Cody Scenic Byway ends – Powell, Big Horn Natl Rec Area	West end of WYO 120 and Buffalo Bill Cody Scenic Byway concurrency
			54.119	87.096		WYO 120 south – Meeteetse, Thermopolis	East end of WYO 120 concurrency
	Big Horn	​	85.065	136.899		WYO 30 south – Burlington
		Emblem	85.665	137.864		WYO 32 north – Powell, Lovell
		​	99.197	159.642		US 310 west / WYO 789 north – Lovell, Billings, Bighorn Canyon Natl Recreation Area	West end of WYO 789 concurrency; US 310 eastern terminus
			101.530	163.397		Airport Rest Area
		Greybull	104.176	167.655		US 14 east (Greybull Avenue) – Shell, Sheridan	East end of US 14 concurrency
		​	108.960	175.354		WYO 36 south (Golf Course Road)
		Basin	111.815	179.949		WYO 30 south (C Street) – Burlington
		​	122.265	196.766		WYO 433 south
		Manderson	122.832	197.679		WYO 31 Spur east – Manderson, Hyattville	Officially WYO 31 Spur; signed as WYO 31
			123.436	198.651		WYO 31 east	Unsigned
	Washakie	Worland	142.079	228.654		US 20 west / WYO 789 south (Big Horn Avenue) – Thermopolis, Hot Springs State Park	East end of US 20 / WYO 789 concurrency
		Ten Sleep	168.500	271.174		WYO 434 south – Big Trails
		​	172.117	276.995		WYO 436 south
			175.978	283.209		WYO 435 east
			176.079	283.372		Eastbound road closure gate (weather depending)
			191.489	308.172		Eastbound road closure gate (weather depending)
	Johnson	​	197.500	317.845		Powder River Pass
			205.566	330.826		Westbound road closure gate (weather depending)
			230.069	370.260		Westbound road closure gate (weather depending)
		Buffalo	233.988	376.567		I-25 BL south / US 87 Bus. south (Main Street) – Casper	South end of I-25 BL / US 87 Bus. concurrency
			234.395	377.222		I-25 BL north / I-90 BL west (Main Street) / US 87 Bus. north	North end of I-25 BL / US 87 Bus. concurrency; south end of I-90 BL concurrency
			234.990	378.180		I-25 / US 87 – Sheridan, Casper	I-25 exit 299
		​	236.517	380.637		I-90 / I-90 BL ends – Sheridan, Gillette	I-90 exit 58; east end I-90 BL concurrency
			236.695	380.924		Eastbound road closure gate (weather depending)
	Sheridan	Ucross	252.255	405.965		US 14 west – Sheridan	West end of US 14 concurrency
		​	279.196	449.322		WYO 341 south – Arvada
	Campbell	​	319.685	514.483		Eastbound road closure gate (weather depending)
			322.648	519.252		WYO 59 north – Broadus	West end of WYO 59 concurrency
		Gillette	329.930	530.971		WYO 50 south / I-90 BL west (Skyline Drive) to I-90 – Buffalo, Moorcroft	West end of BL 90 concurrency
			331.731	533.869		WYO 59 south to I-90 – Douglas	East end of WYO 59 concurrency
			333.053	535.997	128	I-90 west / I-90 BL ends / WYO 51 east – Buffalo	East end of BL 90 concurrency; west end of I-90 concurrency; exit numbers follow I-90
			334.586	538.464	129	Garner Lake Road
		​	338.473	544.719	132	Wyodak Road
		​	346.806	558.130	141	Rozet
	Crook	Moorcroft	358.981	577.724	153	I-90 east / I-90 BL begins – Sundance	East end of I-90 concurrency; west end of BL 90 concurrency
			359.118	577.944		WYO 51 west
			360.186	579.663		US 14 east – Devils Tower, Hulett, Pine Haven	East end of US 14 concurrency
			360.384	579.982		I-90 BL east to I-90	East end of BL 90 concurrency
		​	360.686	580.468		Eastbound road closure gate (weather depending)
	Weston	Upton	380.013	611.572		WYO 116 north – Sundance	West end of WYO 116 concurrency
			380.317	612.061		WYO 116 south	East end of WYO 116 concurrency
		​	380.986	613.138		Upton Rest Area
		Osage	393.479	633.243		WYO 451 west (Oil City Road)
		​	405.786	653.049		Westbound road closure gate (weather depending)
			405.452	652.512		WYO 450 west
		Newcastle	407.127	655.207		US 16 Byp. east
			408.955	658.149		US 16 Byp. west
			409.606	659.197		US 85 – Sundance, Lusk
		​	413.790	665.930		Eastbound road closure gate (weather depending)
			418.874 0.00	674.112 0.00	Wyoming–South Dakota state line
South Dakota	Custer	Custer	26.46	42.58		US 385 south / SD 89 south – Wind Cave National Park, Hot Springs	West end of US 385 / SD 89 concurrency
			26.96	43.39		US 16A east / SD 89 north – Custer State Park	East end of SD 89 concurrency
	Pennington	​	37.49	60.33		SD 87 south (Needles Highway) / Peter Norbeck Scenic Byway – Sylvan Lake, Custer
			37.69	60.66		SD 244 east / Peter Norbeck Scenic Byway – Mount Rushmore
		Hill City	40.51	65.19		US 16 Truck east / US 385 Truck north
			41.06	66.08		US 16 Truck west / US 385 Truck south
		Three Forks	45.00	72.42		US 385 north – Deadwood, Lead	East end of US 385 concurrency
		Keystone Wye	50.60	81.43		US 16A west – Keystone, Mount Rushmore	Directional-T interchange
		​	55.42– 56.19	89.19– 90.43		Rockerville	Interchange; left exits and entrances
		Rapid City	64.19	103.30		US 16 Truck east to I-90 / Catron Boulevard	Future single-point urban interchange (SPUI)
			68.77– 68.85	110.67– 110.80		I-90 BL (St. Joseph Street / Main Street)	One way pair
			68.98	111.01		SD 44 east (Omaha Street)	West end of SD 44 concurrency
			69.20	111.37		SD 44 east (Omaha Street) I-190 begins / West Boulevard	East end of SD 44 concurrency; west end of I-190 concurrency; I-190 southern terminus; exit numbers follow I-190
			69.57	111.96	1C	North Street – Civic Center
			70.64	113.68	1A–1B	I-90 / I-190 ends / US 14 / SD 79 – Gillette, Sioux Falls	Trumpet interchange; US 16 eastern terminus; I-190 northern terminus; east end of I-190 concurrency; signed as exits 1A (west) and 1B (east); I-90 exit 57
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Closed/former       Concurrency terminus

• U.S. Route 116
• U.S. Route 216

• U.S. Route 16A in South Dakota
• Special routes of U.S. Route 16

• Endpoints of US 16
• Highways and Gas Stations- US Hwy 16 Page
• 1937 South Dakota Transportation Map
• 1930 Minnesota Transportation Map
• 1937 Wisconsin Transportation Map