Ardmore is a business, cultural and tourism city in and the county seat of Carter County, Oklahoma, United States. As of the 2007 census estimates, the city had a population of 24,625, while a 2007 estimate has the Ardmore micropolitan statistical area totaling 56,694 residents. Ardmore is located 90 miles (140 km) equidistant from Oklahoma City and Dallas/Fort Worth, Texas at the junction of Interstate 35 and U.S. Highway 70, and is generally considered the hub of the ten-county region in South Central Oklahoma, also known by state tourism pamphlets as Arbuckle Country and Lake and Trail Country. Geologically, Ardmore is situated about 16 kilometers south of the Arbuckle Mountains, and is located at the eastern margin of the Healdton Basin, one of the most oil-rich regions of the United States. Ardmore was named after the affluent Philadelphia suburb and historic Pennsylvania Main Line stop Ardmore, Pennsylvania, which was named after Ardmore, Ireland by the Pennsylvania Railroad in 1873. The name Ardmore is Gaelic signifying high grounds or hills. On April 22, 1966 Ardmore was the site of the worst plane crash in Oklahoma history, which killed 83 people.