U.S. Route 101
The nearly highway's northern terminus is in Tumwater, Washington: the route remains along the Olympic Peninsula's coastal perimeter west, north, and east; the northernmost point on the highway is in Port Angeles. The southern terminus of US 101 is in Los Angeles at the East Los Angeles Interchange, the world's busiest freeway interchange.
Louisiana Highway 101
In the original Louisiana Highway system in use between 1921 and 1955, the modern LA 101 made up parts of several routes, including State Route 1156 from Hayes to Lacassine; State Route 728 from Lacassine to the curve east of Woodlawn; State Route 744 from the curve to Woodlawn; and State Route 24-D west of Woodlawn. The first three were additions to the state highway system in 1930. The last, Route 24-D, indicates an earlier alignment of State Route 24, which was one of the original 98 state highways created in 1921. In 1926, Route 24 was selected to carry the southern portion of US 165 when the numbered U.S. Highway system was implemented. The portion of what is now LA 101 west of Woodlawn was therefore a small part of the original alignment of US 165 until the present alignment alongside the Missouri Pacific Railroad (now the Union Pacific Railroad) line was completed in 1939.