 By 1937, most of the routes that are currently cosigned with it had been designated, most notably US 202.In 1946, SR 4 was truncated to its southern intersection with SR 16 in Rangeley, but was later re-extended along SR 16 to terminate at its current end at Haines Landing in 1951 (the road between SR 16 and Haines Landing had previously been designated SR 144).Most of former SR 4 between SR 16 and the Canada–US border is now part of SR 27.