U.S. Route 90
U.S. Route 90 (US 90) is an east–west United States highway. Despite the "0" in its route number, US 90 never was a full coast-to-coast route; it has always ended at Van Horn, Texas with the exception of a short-lived northward extension to US 62/US 180 near Pine Springs, Texas which lasted less than a year, and the signs on that segment were changed to Texas State Highway 54, traveling from Interstate 10 (I-10) at exit 140A and heading to its northern terminus at US 62/US 180.
U.S. Route 90 in Louisiana
U.S. Route 90 enters Louisiana at the Texas line over the Sabine River as part of Interstate 10 (I-10). Separating at exit 4 and running parallel on the north side of I-10 through Sulphur, before rejoining I-10 east of Westlake, crossing the Calcasieu River, and again splitting from I-10 at exit 31b (running on the south side of I- 10) going through Lake Charles as Fruge, West 4th, then East 4th, before leaving town. In Iowa U.S. 90 intersects with the southern terminus of U.S. Route 165 continuing east through Lacassine, Welsh, Roanoke, Jennings, and Mermentau. East of Mermentau U.S. 90 runs north of and parallel to a section of the Old Spanish Trail through Midland, Estherwood, and Crowley. In Crowley U.S. 90 makes a north then east jog, bringing it close and parallel to I-10, passing through Rayne, Duson, Scott, and then into Lafayette.