U.S. Route 209 (US 209) is a long U.S. Highway in the states of Pennsylvania and New York. Although the route is a spur of US 9, US 209 never intersects US 9, coming within five miles of the route and making the short connection via New York State Route 199 (NY 199). The southern terminus of the route is at Pennsylvania Route 147 (PA 147) in Millersburg, Pennsylvania. The northern terminus is at US 9W north of Kingston in Ulster, New York, where the road continues east as NY 199.

In Pennsylvania, the highway travels through the length of the Delaware Water Gap National Recreation Area, along the southern part of the Poconos in Monroe and Carbon counties through Jim Thorpe and along parts of the defunct historic Lehigh Canal and Lehigh Valley Railroad then over the divide near Nesquehoning into the Schuylkill Valley along Panther Creek. For part of its route in New York, US 209 runs alongside the defunct Delaware and Hudson Canal, which ran from Port Jervis to Kingston, in each case, following the old land road connections connecting the anthracite coal fields of Northeastern Pennsylvania with the industries and heating customers in New York City.

US 209 is one of the original highways in the 1926 U.S. Highway System plan. The route was initially an intrastate highway contained entirely within Pennsylvania. It began at an intersection with US 11 (now US 22 / US 322) in Clarks Ferry (east of Duncannon) and ended at US 6 in Milford. US 209 was extended northward to US 9W in Kingston, New York, in April 1935 and truncated to Millersburg, Pennsylvania, by 1938. The portion of US 209 in New York north of Port Jervis was previously designated as US 6 from 1926 to 1928, U.S. Route 6N from 1928 to 1933, and New York State Route 279 from 1933 to 1935.

US 209 was realigned onto limited-access highways in two locations along its routing during the 1950s. The first is in the Stroudsburg, Pennsylvania, area. Originally just a bypass of Stroudsburg, a portion of this expressway is now also part of Interstate 80 (I-80) while another portion is now also part of PA 33, with the southern end and the portion between I-80 and PA 33 still just US 209. The second is in the Kingston, New York, area. Serving as a bypass of Kingston that connects to the Kingston- Rhinebeck area Kingston-Rhinecliff Bridge, the highway begins west of Kingston along US 209 south of NY 28 in Ulster and ends north of Kingston, at a cloverleaf interchange with US 9W and NY 199, still in Ulster. This also serves as the current northern terminus of US 209, replacing the old terminus at US 9W in Downtown Kingston. When the expressways were finished, US 209's former routing through downtown Stroudsburg was redesignated as US 209 Business, and NY 28 was extended over US 209’s former alignment through downtown Kingston.

Route description

|PA || 150.60 || 242.37 |- |NY || 61.14 || 98.40 |- |Total || 211.74 || 340.76

Although signed as a north–south route in both states for its entire length, US 209 actually runs closer to east–west along its southern sections in Pennsylvania, only gently trending northward. Only at Stroudsburg does it begin to turn more to the north as it begins to follow the Delaware River. In New York it runs almost due northeast for its entire length.

Much of the highway in both states is a two-lane road, running through narrow mountain valleys, but there are expressway portions. In Pennsylvania, one near Stroudsburg connects concurrencies with PA 33 and Interstate 80 (I-80); in New York, the north end is an expressway.

Millersburg to Jim Thorpe

From the southern terminus at PA 147 in Millersburg, US 209 runs alongside the Berry Mountain ridge through the Lykens Valley in northern Dauphin County, a rural valley that is home to an Amish community. In the Lykens Valley, the route passes through Elizabethville before continuing east through Lykens and Williamstown. The road continues into Schuylkill County, finally climbing a valley headwall near Tower City to intersect I-81 on the other side, then continues on to Tremont. Beyond that, the generally straight route starts to curve a little more frequently into Pottsville, after which it follows the upper Schuylkill River as it heads into lightly populated areas in the Coal Region such as Port Carbon, Cumbola, New Philadelphia, and Middleport on its way to Tamaqua.

Several miles beyond, US 209 crosses into Carbon County at Lansford, where it nestles between Nesquehoning, Sharp, and Pisgah mountains until it finally turns slightly to the north just before Nesquehoning. From there it follows the Nesquehoning Creek valley down to the Lehigh River, which US 209 follows southeasterly through Jim Thorpe to Lehighton. At the south end of the town, it crosses the river and resumes its north-trending eastward course, which brings it to an interchange at I-476 (Pennsylvania Turnpike Northeast Extension).

Jim Thorpe to Matamoras

Once again, there are no major settlements along US 209 as it heads through isolated valleys, this time with more agricultural use evident, into Monroe County and eventually to its absorption into PA 33. US 209 Bus. leaves the road at Sciota for travelers wishing to bypass the expressway.

At the next exit, US 209 takes its own short branch of expressway several miles to I-80 just outside Stroudsburg. It stays with the Interstate through the borough and neighboring East Stroudsburg from exits 304 to 309, one of the last exits before the state line.

From this point on, US 209 runs much more northerly, reconnecting with US 209 Bus. after several miles and taking its more firmly northeast bearing to eventually run along the Delaware River shortly after entering Pike County, its last in the state. This segment provides access to New Jersey via toll bridges at Dingman's Bridge and Milford Crossing, where US 206 comes to its northern end. Just beyond the latter bridge, the road reaches Milford, where US 6 joins it.

The two highways eventually start to run alongside I-84, and development picks up as they approach Matamoras, the easternmost town in the state. After crossing under the interstate at its final Pennsylvania interchange, they form the borough's main street along Pennsylvania Avenue and cross into New York via the Mid-Delaware Bridge.

Mid-Delaware Bridge to Kingston US 6 and US 209 remain concurrent as they enter Port Jervis, but after less than a mile US 209 strikes out to the northeast again on its own. After leaving the city, it enters the valley between the Shawangunk Ridge and the Catskill Plateau to its west, following the Neversink River until crossing it just prior to the hamlet of Cuddebackville. The scenery is rural and the settlements along the road are few, with only one blinker between Port Jervis and the Sullivan County line. In Wurtsboro, shortly after the NY 17 (future I-86) interchange, the route reaches a traffic light at Sullivan Street.

The road follows along some of the old Delaware and Hudson Canal, a National Historic Landmark and passes Wurtsboro Airport, out of the county into Ulster County, and eventually reaches another village, more bustling Ellenville. Just past it, in the hamlet of Napanoch, it picks up its first concurrency partner since US 6, NY 55. These two routes run together as Rondout Creek crosses and eventually runs alongside the road.

At another small hamlet, Kerhonkson, NY 55 leaves to join US 44 at the latter's western terminus. US 44 and NY 55 offer access ultimately to Poughkeepsie, to the east. The valley begins to widen as another road, NY 213, joins for a mile before leaving at a blinker in downtown Stone Ridge. To the north, the road eventually becomes a two-lane expressway, then a four-lane freeway just short of NY 28 just west of Kingston, just inside the Catskill Park.

After turning to the east again, US 209 crosses the New York State Thruway (I-87) but does not have an exit. The eastbound highway remains a freeway to the Kingston–Rhinecliff Bridge. US 209, however, does not make it that far, becoming NY 199 where it crosses over US 9W.

History US 209 follows a straight, northeasterly course for almost its entire length within New York. This corridor, first used for long-distance transport by the Old Mine Road in colonial times and then the historic Delaware and Hudson Canal in the early 19th century, keeps it in the scenic valley between the Catskill Plateau and the Shawangunk Ridge. Except for the freeway section at the northern end—the remnant of a much more ambitious plan to make the entire roadway one—US 209 remains a two-lane rural road for much of its length in the state. The small communities along it are separated by great distances, and the road is a vital access link.

Pennsylvania Before the advent of the U.S. Highway System, the alignment of US 209 in Pennsylvania carried several designations. By 1920, the Gap Way was signed to run from Philadelphia to East Stroudsburg, where it met the modern alignment of U.S. 209, running along that road to the New York border.Rand Mcnally And Company. . [New York?: Rand McNally & Co.; Newark, N.J.: Berwick Hotel distributor, ?, 1920] Map. Retrieved from the Library of Congress, <www.loc.gov/item/88695915/>. On May 31, 1911, as part of the Sproul Road Bill, the highway was assigned several Legislative Route numbers, each corresponding to a specific section of what would become US 209. The segment of the route from Duncannon north to Millersburg was part of Legislative Route 1. From Millersburg east to Pottsville, the highway was referenced as LR 199. Between Pottsville and Lehighton, the road carried LR 162. The section connecting Lehighton to Stroudsburg was given LR 164. Lastly, the segment from Stroudsburg to Milford was designated LR 167. The future US 6 / US 209 concurrency between Milford and the state line carried LR 8.

The Pennsylvania portion of US 209 dates back to the formation of the U.S. Highway System in 1926. At the time, US 209 began at US 11 (today US 22 / US 322) east of Duncannon and ended at US 6 in Milford. Northeast of Milford, US 6 continued alone to Matamoras and across the Delaware River into New York. Between Duncannon and Millersburg, US 209 was routed along the eastern banks of the Susquehanna River on what is now PA 147. In the Poconos, US 209 ran along the modern US 209 Business. US 209 was extended northward to Kingston, New York, , creating an overlap with US 6 from Milford to the state line. Meanwhile, US 209 was truncated by 1938 to end in Millersburg while the former routing of US 209 from Clarks Ferry to Millersburg became part of an extended US 15.

In the summer of 1962, the routing of US 209 was altered in the vicinity of Stroudsburg. At what is now the interchange between US 209 and US 209 Business, US 209 broke from its previous alignment and continued east to a newly built freeway (modern PA 33). PA 115, which was concurrent with US 209 from Brodheadsville to the freeway, continued south on the expressway while US 209 proceeded north. At the present-day split between PA 33 and US 209, US 209 followed the east fork, leaving the west fork with no designation. US 209 then followed its current alignment around Stroudsburg, running concurrent to I-80 from exit 46A to exit 52 (now exits 304 and 309, respectively). It left I-80 at exit 52 and rejoined its previous alignment northeast of the borough. The old alignment through the borough was redesignated as US 209 Business. Part of US 209's new alignment east of Stroudsburg was previously part of PA 402. By 1972, PA 115 was truncated to Brodheadsville and the length of the north–south freeway near Stroudsburg was designated PA 33, overlapping US 209 for roughly two miles.