PA 940 was first designated in 1928 between White Haven and PA 115 in Blakeslee. The road between Blakeslee and Pocono Summit was part of PA 115 while PA 615 was designated between PA 115 in Pocono Summit and PA 90 (now PA 390) west of Paradise Valley. PA 940 was extended east to U.S. Route 611 (US 611) in Swiftwater in 1935, replacing a portion of PA 115. PA 615 was decommissioned in 1946. PA 940 was extended west to US 309 in Hazleton by 1950. PA 196 was designated onto the roadway between Mount Pocono and Paradise Valley in 1956. PA 940 was moved to its current alignment between Pocono Summit and Paradise Valley in 1964 after the roadway in Pocono Summit was upgraded to a divided highway; the route replaced PA 196 between Mount Pocono and Paradise Valley while PA 314 was designated along the former PA 940 between Pocono Summit and Swiftwater.