 From the western terminus at SR-126 (1900 West) in Ogden, the route is named 21st Street, a standard two-way, east–west minor arterial, with an interchange with I-15 near the west end.This section of the route is about long.About half a mile west of the eastern terminus at SR-204 (Wall Ave), as it starts to pass over railroad tracks, the route splits into a one-way pair, with the eastbound lanes continuing as 21st street, and the westbound lanes located one block to the north as 20th Street.