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 151 while on the east side is the Arkansas River. After crossing the dam, the route ends at US-64/US-412 at another trumpet interchange, west of Sand Springs. Keystone Dam was completed in 1964. The dam was first shown as a state highway on the 1965 state highway map. No SH-151 shield was shown on this map, however; presumably it was omitted for space reasons. The highway would remain unlabeled on the official state maps until the 2008 edition. Oklahoma State Highway 151 State Highway 151 (abbreviated SH-151 or OK-151) runs across Keystone Dam in northeastern Oklahoma. Its entire length is within