Oklahoma County, Oklahoma Oklahoma County, Oklahoma Oklahoma County is a county located in the central part of the U.S. state of Oklahoma. As of the 2010 census, the population was 718,633, making it the most populous county in Oklahoma. The county seat is Oklahoma City, the state capital. Oklahoma County is at the heart of the Oklahoma City Metropolitan Statistical Area. Oklahoma County is one of seven counties in the United States to share the same name as the state it is located in (the other six counties are Arkansas County, Hawaii County, Idaho County, Iowa County, New York County (known commonly as
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