Oklahoma State Highway 270 1979, US-270 ran through Oklahoma City on surface streets. It left the city and ran through Choctaw concurrent with US-62. US-270 split away from US-62 in Harrah, and continued on to Shawnee on what is now SH-270. On March 5, 1979, US-270 was rerouted to run concurrent with Interstate 40 from south of Calumet in Canadian County through the Oklahoma City metro, exiting the Interstate onto a surface alignment in Shawnee. Presumably, SH-270 was commissioned the same date. The realignment of US-270, with SH-270 on the old alignment between Harrah and Shawnee, appears on the 1979 state map. SH-270 followed
Oklahoma State Highway 8 Oklahoma Transportation Commission applied the national highways to Oklahoma's state highway system on 1926-11-26. Three U.S. highways were assigned to portions of what was then SH-8: U.S. Highway 64 was added to a segment of highway south of Cherokee, U.S. Highway 66 was added between Bridgeport and Geary, and U.S. Highway 70 was added from the Texas state line to Randlett. US-66 and 64 merely ran concurrently with SH-8. However, US-70 completely replaced the state highway, which was truncated so that its southern terminus was at US-70 in Randlett. By 1936, several U.S. highways had been added to the system