Interstate 44 (abbreviate I-44) is an interstate highway in the central United States. Its western terminus is in Wichita Falls, Texas at concurrency with US 277, US 281 and US 287; its eastern terminus is in St. Louis at Interstate 55 (the Federal Highway Administration considers its end to be at the Missouri-Illinois State Line ). Interstate 44 is one of five interstates built to bypass U.S. Route 66; this highway covers the section between St. Louis and Oklahoma City. Virtually the entire length of the Interstate east of Springfield, Missouri was once US 66 which was upgraded from two to four lanes between 1949 and 1955. The section of I-44 west of Springfield was built further south than US 66 in order to connect Missouri's section with the already completed Will Rogers Turnpike, which Oklahoma wished to carry their part of I-44.