High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Tyler County is a county located in the U.S. state of West Virginia. As of 2000, the population was 9,592. The County is named after John Tyler, Sr., father of President John Tyler. Its county seat is Middlebourne. According to the U.S. Census Bureau, the county has a total area of 261 square miles (675 km²), of which, 258 square miles (667 km²) of it is land and 3 square miles (8 km²) of it (1.20%) is water.