U.S. Route 15 (US 15) is United States Numbered Highway that runs from Walterboro, South Carolina, north to Painted Post, New York. In Pennsylvania, the highway runs for 194.89 miles (313.65 km), from the Maryland state line just south of Gettysburg, north to the New York state line near Lawrenceville.

US 15 enters Pennsylvania south of Gettysburg, Adams County, from Frederick County, Maryland, on a freeway alignment. The route heads to the north and bypasses Gettysburg, where the route has an interchange with US 30. The freeway alignment ends at York Springs, carrying US 15 on a four-lane expressway, then becoming a four-lane arterial road in Dillsburg, until the route upgrades to a freeway again. The route continues north toward Harrisburg, where the freeway terminates again as US 15 joins with US 11. The two routes begin to follow the west shore of the Susquehanna River with limited-access sections until they split across the river from Sunbury. US 15 continues north into Williamsport, joining Interstate 180 (I-180) and US 220. At I-180's western terminus, US 220, signed south, heads due west toward Jersey Shore and Lock Haven, while US 15 turns due north through Mansfield and crosses into New York near Lawrenceville, Tioga County.

The majority of US 15 is four lanes, alternating between limited and unlimited access. There are two segments where the road is two lanes. One is from East Pennsboro Township, Cumberland County, just north of the I-81 interchange, to just south of Duncannon. The other is between White Deer and South Williamsport. The segment between Williamsport and the New York state line will eventually be designated I-99.

With the adoption of the U.S. Numbered Highway System, US 15 originally terminated at Harrisburg, while US 111 serviced the modern route north of that point. In 1937, US 15 was extended north to the New York state line, effectively replacing US 111 north of Harrisburg. However, instead of replacing US 111's old routing directly, US 15 ran along the east bank of the Susquehanna River between Harrisburg and Williamsport. Meanwhile, the road on the western bank of the river was Pennsylvania Route 14 (PA 14) between Lemoyne and Duncannon, US 11 between Duncannon and Shamokin Dam, and PA 404 between Shamokin Dam and Williamsport.^[2] In 1941, US 15 was rerouted to follow the western bank of the river between Harrisburg and Williamsport, replacing PA 14 between Lemoyne and Duncannon, running concurrent with US 11 between Lemoyne and Shamokin Dam, and replacing the entire length of PA 404. The former alignment of US 15 on the east side of the river became PA 14.^[3][4]

The section of US 15 north of Williamsport will gain the additional designation of I-99 when the connection from I-76 to I-86 is completed. No additional work is needed to upgrade this stretch, as it is already up to Interstate standards.^[5]

As part of the construction of the Central Susquehanna Valley Thruway, US 15 is planned to be rerouted to the new freeway between Selinsgrove and Union Township, bypassing Shamokin Dam. The former alignment of US 15 through Shamokin Dam will be designated as US 15 Business, partly running concurrent with US 11.^[6]

County	Location[7]	mi[1]	km	Exit	Destinations	Notes
Adams	Freedom Township	0.0	0.0		US 15 south (Catoctin Mountain Highway) – Frederick	Continuation into Maryland
		1.74	2.80		US 15 Bus. (Steinwehr Avenue)
	Cumberland Township	5.88	9.46		PA 134 (Taneytown Road)
	Mount Joy Township	8.15	13.12		PA 97 south (Baltimore Pike)	Northern terminus of PA 97; access to Gettysburg National Military Park
	Straban Township	10.01	16.11		PA 116 (Hanover Road)
		11.52	18.54		US 30 (York Street)	Access to Gettysburg College
		14.71	23.67		PA 394 / US 15 Bus. south – Hunterstown	Northern terminus of US 15 Bus.; access to Gettysburg College
	Tyrone Township	19.59	31.53		PA 234 – East Berlin, Heidlersburg
	Huntington Township	23.59	37.96		PA 94 – Hanover, York Springs
York	Dillsburg–Carroll Township line			Northern end of limited-access section
		32.51	52.32		PA 74 south (Baltimore Street) to PA 194 – Dillsburg, York	Southern end of PA 74 concurrency
		32.72	52.66		PA 74 north (York Road) – Williams Grove, Carlisle	Northern end of PA 74 concurrency
Cumberland	Upper Allen Township			Southern end of freeway section
		36.32	58.45		Lisburn Road
		37.68	60.64		PA 114 – Bowmansdale, Mechanicsburg
		38.72	62.31		Winding Hill Road / Cumberland Parkway
		39.29	63.23		I-76 / Penna Turnpike – Pittsburgh, Philadelphia	Exit 236 on I-76 / Turnpike
	Lower Allen Township	40.31	64.87		Wesley Drive / Rossmoyne Road
		41.03	66.03		Slate Hill Road
		41.76	67.21		Lower Allen Drive
	Camp Hill	42.49	68.38		US 11 south / PA 581 to I-81 / I-83 – Carlisle, Harrisburg, York	Exit 5 on PA 581; southern end of US 11 concurrency
				Northern end of freeway section
		42.99	69.19		PA 641 west (Trindle Road) – Mechanicsburg	Eastern terminus of PA 641
	Camp Hill–East Pennsboro Township line				M. Harvey Taylor Bridge – Harrisburg	Northbound exit and southbound entrance
	East Pennsboro Township	47.34	76.19		PA 944 west (State Street)	Eastern terminus of PA 944
		50.35	81.03		I-81 (Capital Beltway) – Carlisle, Harrisburg	Exit 65 on I-81
Perry	Marysville	52.61	84.67		PA 850 west (Valley Street)	Eastern terminus of PA 850
	Penn Township			Southern end of freeway section
	Penn Township–Duncannon line	60.10	96.72		PA 274 west – Duncannon	Eastern terminus of PA 274
Dauphin	Reed Township	62.59	100.73		US 22 / US 322 – Harrisburg, Lewistown
Perry	Watts Township			Northern end of freeway section
	Buffalo Township	72.78	117.13		PA 34 south (Hunters Valley Road) – Newport	Northern terminus of PA 34
	Liverpool	74.54	119.96		PA 17 west – Millerstown	Eastern terminus of PA 17
	Liverpool Township	78.90	126.98		PA 104 north – Middleburg	Southern terminus of PA 104
Juniata	No major junctions
Snyder	Penn Township			Southern end of freeway section
		91.15	146.69		PA 35 south – Selinsgrove	Northern terminus of PA 35
	Monroe Township	95.58	153.82		US 522 south – Selinsgrove	Northern terminus of US 522
				Northern end of freeway section
	Shamokin Dam	96.63	155.51		PA 61 south / PA 147 south – Sunbury	Interchange; northern terminus of PA 61; southern end of PA 147 concurrency
		96.98	156.07		US 11 north – Northumberland, Danville	Northern end of US 11 concurrency
Union	Union Township				PA 147 north (Central Susquehanna Valley Thruway) to I-80 / I-180 – Milton	Interchange; northern end of PA 147 concurrency
		101.83	163.88		PA 304 west – New Berlin	Eastern terminus of PA 304
	East Buffalo Township–Lewisburg line	105.79	170.25		PA 45 (Market Street) – Lewisburg|Lewisburg Business District
	Lewisburg	106.25	170.99		PA 192 west (Buffalo Road) – Cowan	Eastern terminus of PA 192
	Kelly Township			Southern end of freeway section
		110.21	177.37		PA 642 east (Mahoning Street) – Milton, West Milton, Pottsgrove	Western terminus of PA 642
	White Deer Township	111.78	179.89		New Columbia
		112.57	181.16		I-80 – Bloomsburg, Bellefonte	Exit 210 on I-80
		114.29	183.93		Watsontown, White Deer
				Northern end of freeway section
	Gregg Township	116.81	187.99		PA 44 (Bridge Avenue) – Jersey Shore, Dewart
Lycoming	Clinton Township	122.66	197.40		PA 54 east – Montgomery	Western terminus of PA 54
	South Williamsport	128.34	206.54		PA 554 south (South Market Street)	Northern terminus of PA 554
		128.95	207.52		PA 654 west (Southern Avenue)	Eastern terminus of PA 654
	Williamsport	129.35	208.17	Southern end of freeway section
				27A	I-180 east / US 220 north – Montoursville, Muncy	Southern end of I-180/US 220 concurrency
		129.85	208.97	27B	Hepburn Street	Eastbound exit and westbound entrance
		130.53	210.07	28	Maynard Street	Access to Pennsylvania College of Technology
		131.67	211.90	29	Future I-99 south / US 220 south – Lock Haven I-180 ends	Northern end of US 220 concurrency; current southern terminus of I-99; exit number not signed southbound
		132.09	212.58	136	Third Street	Northbound exit and entrance
		132.37	213.03	136	Fourth Street	Southbound exit and entrance
	Old Lycoming Township	132.99	214.03	137	Foy Avenue / High Street / Lycoming Creek Road
	Lycoming Township	136.34	219.42	140	Hepburnville
		138.90	223.54	143	PA 973 – Perryville, Cogan Station	Southbound exit only
	Lewis Township	144.00	231.75	148	PA 14 north – Trout Run, Canton	Southern terminus of PA 14
	Cogan House Township	148.27	238.62	152	Cogan House	Southbound exit and entrancd; access via State Route 4011
		148.89	239.62	152		Northbound exit and entrance; access via State Route 4011
		150.90	242.85	155	PA 184 west – Steam Valley[8][9]	Eastern terminus of PA 184
	Jackson Township	153.68	247.32	158	PA 284 west – Buttonwood, English Center	Eastern terminus of PA 284
Tioga	Liberty	158.81	255.58	162	PA 414 – Liberty, Morris
		160.96	259.04	165	Sebring
	Blossburg	168.08	270.50	172	Blossburg
	Richmond Township	175.55	282.52	179	US 15 Bus. north / PA 660 west – Canoe Camp, Covington	Southern terminus of US 15 Bus.; eastern terminus of PA 660
	Mansfield	177.82	286.17	182	US 6 – Mansfield, Wellsboro	Access to Hills Creek State Park and Mansfield University
	Richmond Township	179.16	288.33	183	US 15 Bus. south (Main Street)	Southbound exit and northbound entrance; northern terminus of US 15 Bus.
	Tioga Township	187.65	301.99	191	PA 287 – Tioga, Tioga Junction
	Lawrence Township	192.46	309.73	196	PA 49 – Elkland, Lawrenceville	Access to Cowanesque Lake
	Lawrenceville	194.89	313.65		I-99 north / US 15 north – Corning	Continuation into New York
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Electronic toll collection       Incomplete access

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• Pennsylvania Highways: US 15
• US 15 at AARoads.com
• Pennsylvania Roads - US 15

U.S. Route 15
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