U.S. Route 11 is a north–south United States highway extending 1,645 miles (2,647 km) across the eastern United States. The southern terminus of the route is at U.S. Route 90 in the Bayou Sauvage National Wildlife Refuge in eastern New Orleans, Louisiana. The northern terminus is at the United States-Canada border in Rouses Point, New York. The route continues across the border in Canada as Quebec Route 223. U.S. 11, created in 1926, largely follows the route of the original plan.

Until 1929, U.S. 11 ended just south of Picayune, Mississippi at the Pearl River border with Louisiana. It was extended through Louisiana after that.

The Maestri Bridge, which carries U.S. 11 across Lake Ponchartrain, served as the only route to New Orleans from the east for six weeks after Hurricane Katrina due to its sturdy construction. The storm virtually destroyed the Twin Span Bridge on I-10 and damaged the Fort Pike Bridge on US 90.

Interstate 81, constructed in the 1960s, parallels the route of U.S. 11 in many areas. Beyond I-81's southern terminus, other interstates run along corridors paralleling U.S. 11, specifically I-59, which is joined to I-81 by I-40, I-75, and I-24.

The southernmost point of U.S. Route 11 is at an intersection with U.S. Route 90 (Chef Menteur Highway) in the far eastern section of New Orleans, in the community of Viavant. Route 11 heads to the north, passing to the east of a bayou of Lake Pontchartrain. The route passes Chevee Bayou and a short stretch of land in the community of Village de l'Est. The route makes a short curve to the northeast, and returns to the north soon after. U.S. Route 11 begins to parallel Interstate 10, until interchanging at Exit 254 in Irish Bayou. There, Route 11 passes to the east of the bayou and continues north onto a causeway over Lake Pontchartrain.

Now on the causeway, U.S. Route 11 runs west of Interstate 10 (which was built later) and makes landfall in the community of North Shore. There, U.S. Route 11 gains the name Pontchartrain Drive and enters the community of Eden Isles. In Eden Isles, Route 11 passes the Oak Harbor Golf Club and near Fritchie Park. The highway passes Palm Lake, a small local waterbed, and intersects with Louisiana Highway 433 (known locally as Old Spanish Trail). Route 11 and LA-433 become concurrent for a short distance until Front Street, where Route 11 turns to the northeast.

Route 11 continues to the northeast, away from LA-433, and into the community of Slidell. In Slidell, the route heads along Front Street, passing to the east of commercial buildings and to the west of residences, creating an arterial in downtown Slidell. After the intersection with Erlanger Road, Route 11 intersects with U.S. Route 190 (Fremaux Avenue), which becomes concurrent along Front Street. Routes 11 and 190 continue to the north, intersecting with many locally maintained roads in Slidell. At the intersection with Gause Boulevard and Gause Boulevard West, Route 190 turns to the west.

Route 11 continues to the northeast along Front Street, until the intersection with Indiana Avenue, where it changes onto the alignment of Highway 11. There, Route 11 leaves Slidell for the community of North Slidell, where it comes upon an interchange with Interstate 12 (the West Florida Republic Parkway) at Exit 83. After the partial-cloverleaf interchange, the highway intersects with many local roads in North Slidell and eventually into the community of Alton. North of Alton, Route 11 intersects with Highway Department Road, and eventually parallels to the west of Interstate 59.

Route 11 continues to the northeast, intersecting with Louisiana Highway 41 (Watts Road) and locally maintained Watts Road. This serves as the southern terminus for LA-41. Route 11 turns to the right and intersects with Louisiana Highway 41 Spur, an auxiliary route of the highway that intersected recently in the community of Pearl River. At the intersection, Route 11 turns off of Main Street and interchanges with Interstate 59, paralleling it for a short distance to the north before becoming concurrent at the West Pearl River.

Route 11 and Interstate 59 continue to the northeast, interchanging with a former alignment of U.S. Route 11 that went to east from Interchange 5B. The highways parallel the West Pearl River and eventually, Honey Island Swamp Road. At Honey Island Swamp Road, Interstate 59 and U.S. Route 11 approach Interchange 11, the final interchange in Louisiana. At the Pearl River, the two highways cross the state line and enter Mississippi.

U.S. Route 11 enters the state of Mississippi along Interstate 59, passing through several directions of trees. After a short distance, Route 11 and Interstate 59 interchange at Exit 1 with Mississippi Highway 607, where 607 ends and U.S. Route 11 takes over its northeastern alignment away from Interstate 59. Route 11 generally parallels I-59 across Mississippi, serving as a local business route and following city streets through communities such as Hattiesburg, Laurel, and Meridian. It leaves the state east of Meridian concurrent with U.S. Route 80, entering the state of Alabama.

U.S. Route 11 and U.S. Route 80 split three miles (5 km) into Alabama near Cuba, with U.S. 80 following an eastward track toward Demopolis. U.S. 11, in contrast, continues to parallel the I-20/I-59 freeway through Livingston to Eutaw, where U.S. 11 joins U.S. Route 43. The overlapping routes proceed northeast to Tuscaloosa, where U.S. 43 splits from U.S. 11 and heads north. U.S. 11, however, continues along the I-20/I-59 corridor to Birmingham. U.S. 11 overlaps I-20/59 for approximately 12 miles (19 km) between Woodstock and Bessemer. From Bessemer into Birmingham, the route is locally known as the "Bessemer Superhighway." U.S. 11 is co-signed with Alabama state route 5 between Woodstock and Birmingham. U.S. 11 thru the western side of Birmingham is known as the Bessemer Superhighway and 3rd Avenue West. It passes near the Alabama State Fairgrounds, Rickwood Field (one of the oldest baseball stadiums in America) and Legion Field (known for hosting football games). On the east side of Birmingham, U.S. 11 is known locally as 1st Avenue North and as Roebuck Parkway.

West of downtown Birmingham, U.S. 11 intersects U.S. Route 78. U.S. 78 turns east onto U.S. 11, forming an overlap as the roadway enters the heart of the city. In the midst of the city center, U.S. 78 breaks from U.S. 11, progressing south of U.S. 11 as the two routes exit the city. East of downtown, I-20 splits from I-59, with U.S. 11 following I-59 to the northeast. U.S. 11 passes through Gadsden and Fort Payne before crossing into Georgia ten miles (16 km) northeast of Hammondville.

Throughout Alabama, U.S. 11 is paired with unsigned Alabama State Route 7.

After entering the state from Alabama, U.S. Route 11 and State Route 58 travel northeast, parallel to Interstate 59, through the valley between Sand Mountain and Lookout Mountain. The route passes through the county seat of Dade County, Trenton, where it is briefly cosigned with State Route 136. In the community of Wildwood, U.S. Route 11 and State Route 58 serve as the eastern terminus of State Route 299 before continuing north into Tennessee.

U.S. Route 11 sees an Average Annual Daily Traffic of 5,000 vehicles or more north of Trenton.[dead link] However, most of the route's through traffic has been diverted to Interstate 59, which closely parallels the route not only in Georgia, but also in Alabama and Mississippi.

US 11 enters Tennessee west of Chattanooga. The route, concurrent with State Route 38 from the state line north, runs parallel to Interstate 24 for three miles (5 km) to an intersection with Cummings Highway (U.S. Route 41/U.S. Route 64/U.S. Route 72/State Route 2). While SR 38 terminates here, US 11 follows the highway east into downtown Chattanooga. At the intersection of Broad Street and East 23rd Street, US 11 and US 64 separate from US 41 and US 72 and follow East 23rd east through downtown. The routes briefly overlap with US 41, here concurrent to U.S. Route 76, on Dodds Avenue before resuming an easterly progression on Brainerd Road thereafter called Lee Highway. The road is also called Lee Highway in Southwestern Virginia.

East of downtown, I-24 terminates while Interstate 75 continues east along the I-24 right-of-way. US 11 and US 64 continue to the northeast, paralleling I-75 to Cleveland. In downtown Cleveland, US 64 separates from US 11, following U.S. Route 74 east out of the city.

US 11 remains close to I-75 as it heads north, passing through Athens, Sweetwater, Loudon, and Lenoir City before entering Farragut. On the western edge of town, US 11 merges with U.S. Route 70 at Dixie Lee Junction to form Kingston Pike. The routes remain joined for just over 20 miles (32 km) as they pass through Farragut and West Knoxville before diverging again in downtown Knoxville.

In eastern Knoxville, US 11 splits into U.S. Route 11W and U.S. Route 11E, with US 70 following US 11E. Both routes follow a northeasterly routing through northeastern Tennessee, with US 11W taking a more northerly course than its eastern alternate. While US 11W passes through Blaine, Rutledge, Bean Station, Rogersville, Surgionsville, Church Hill, Mount Carmel and Kingsport, US 11E branches south to connect Jefferson City, Morristown, Greeneville, Jonesborough and Johnson City. The two routes cross into Virginia at Bristol.

US 11W and US 11E rejoin as US 11 in Bristol less than a mile north of the Tennessee-Virginia state line. As Lee Highway, US 11 proceeds northeastward through Abingdon, Wytheville and Radford. In this area, Interstate 81 was constructed parallel to US 11.

At Christiansburg, US 11 joins U.S. Route 460 and the two routes overlap for 28 miles (45 km) to Salem, where the two highways split. US 11 winds through Roanoke on several roads, sometimes opposite the signed direction.

From Roanoke, the highway continues through Buchanan, Lexington, Staunton, Harrisonburg and Winchester in the Shenandoah Valley. Interstate 81 was constructed parallel to US 11 through many of these cities, although it generally bypassed the smaller towns. US 11 enters West Virginia about 10 miles (16 km) northeast of Winchester.

US 11 enters West Virginia less than 200 yards (180 m) southeast of I-81. As the Winchester Pike, US 11 heads northeast for about 35 miles (56 km) through Berkeley County, passing through Inwood, Martinsburg, and Falling Waters before crossing the Potomac River into Maryland.

In Maryland, US 11 passes over the Potomac River into Williamsport and through Hagerstown in Washington County before crossing the Mason-Dixon Line into Pennsylvania. Interstate 81 was constructed along much the same route in the 1960s.

US 11 and I-81 enter Pennsylvania south of Greencastle. Known as the Molly Pitcher highway, US 11 follows I-81 northeast through the Cumberland Valley, running parallel to each other as they pass through Chambersburg, Shippensburg, and Carlisle. Northeast of Carlisle in Middlesex, US 11 interchanges with the Pennsylvania Turnpike (Interstate 76) and I-81 in succession. US 11, now to the south of I-81, continues eastward into the western suburbs of Harrisburg as the Carlisle Pike.

In Camp Hill, a close suburb of Harrisburg, US 11 stops paralleling I-81 and joins U.S. Route 15 northward through the western suburbs of Harrisburg. As the road exits the Harrisburg area, US 11 and US 15 begin to parallel the Susquehanna River as both head northward. The two routes remain overlapped to an intersection in Shamokin Dam, where US 15 branches off to the northwest, following the path of the Susquehanna's West Branch northward. US 11, in contrast, continues to parallel the main Susquehanna River, passing through municipalities such as Danville, Bloomsburg, and Berwick prior to reaching Wilkes-Barre.

In Wilkes-Barre, US 11 breaks from the Susquehanna and begins to run parallel to I-81 once more. From Wilkes-Barre, the highway goes through nearby Scranton, becoming the North Scranton Expressway north of downtown. In Clarks Summit, just north of Scranton, US 11 intersects U.S. Route 6. US 6 joins US 11 westward to Factoryville, where US 11 separates from US 6 and resumes its northerly trek through Susquehanna County to the New York-Pennsylvania border.

US 11 proceeds northwestward through New York from the Pennsylvania border to Binghamton. US 11 and I-81 continue to parallel each other as they head north through Cortland and Syracuse. The route continues northward to Watertown. US 11 heads northeast from Watertown, passing along the northern edge of the Fort Drum Military Reservation and traversing a number of towns and villages, including Canton and Potsdam. US 11 passes north of Adirondack Park passing through Malone. At Rouses Point, US 11 joins New York State Route 9B and heads north to the Canada–United States border, becoming QC 223.