PA 390 was designated in 1928 to run between PA 90 (now PA 191) in Mountainhome and PA 90/PA 507 in Newfoundland, with PA 90 following the current route south of Mountainhome. The route was realigned in the 1930s to head north from Canadensis to its current terminus at PA 507 north of Tafton, with PA 290 (now PA 447) extended along the former alignment between Canadensis and Newfoundland. PA 90 was shifted to a more direct alignment between Paradise Valley and Cresco in the 1940s, with the former section becoming unnumbered. PA 390 was extended south to its current terminus at PA 940 in the 1970s.