U.S. Route 11 in Louisiana

U.S. Highway 11 in Louisiana (US 11) runs 31.11 miles (50.07 km) from the national southern terminus at US 90 in New Orleans to the Mississippi state line south of Picayune. The route parallels Interstate 10 (I-10) across Lake Pontchartrain and into Slidell, serving as that city's major north–south arterial. After crossing I-12, it parallels I-59 to Pearl River, at which point the two highways proceed concurrently across the state line.

The portion of US 11 between Slidell and Pearl River was once part of the Old Spanish Trail, an early auto trail that largely became the route of US 90 when the numbered U.S. Highway System was implemented in 1926. US 11 originally terminated in Mississippi just northwest of what is now the John C. Stennis Space Center. In 1937, US 90 was relocated onto a new route bypassing Slidell and Pearl River, significantly reducing the distance between New Orleans and the Mississippi Gulf Coast. US 11 was extended into Louisiana two years later over the former alignment of US 90, and the two routes proceeded concurrently into Downtown New Orleans. In 1951, US 11 was cut back to its current southern terminus at US 90 in Eastern New Orleans.