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 23 the current western terminus of SH-15 was made with what was then Farm to Market Road 1265 to Booker and TX-117 back to Oklahoma.) The connection to Kansas north of US-64 did not exist as a state highway prior to 1957; it first appears on the 1958 state highway map, also signed as SH-15. The highway is not shown as overlapping US-64 and US-270 to Elmwood. SH-23 is first shown replacing SH-15 on the 1959 map, implying the change took place in 1958. Again, SH-23 is not shown as overlapping US-270; it would not be shown as doing such until