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 78 its entirety in 1955, most likely to match the route number of TX-78. SH-78 was originally designated as a route from Boise City to the Texas Border. This route became US 385 in 1955. Oklahoma State Highway 78 State Highway 78 is long (97 km) state highway in southern Oklahoma. It runs from the Red River (where it crosses into Texas as State Highway 78) to Tishomingo. It has no lettered spur routes. State Highway 78 enters Oklahoma across the Red River on the State Highway No. 78 Bridge at the Red River, near the unincorporated community of Karma. Near