History / Settlement
Clay County was named for Henry Clay and abandoned during the Civil War
Clay County was split from Cooke County in 1857, named for Kentucky statesman Henry Clay, and had fewer than 110 residents by 1860 before settlers abandoned it during the Civil War.
Clay County was created on December 24, 1857. The Texas Legislature split it off from Cooke County. The county was named after Kentucky statesman Henry Clay. The same act required the county seat to be named Henrietta. By 1860 only 109 people lived there. When the Civil War pulled troops away from the frontier, raids made the area dangerous. By 1862 settlers had left and the county was officially unorganized. Henrietta was reported deserted and was later burned.
Settlers came back after the war. Henrietta was incorporated. The Fort Worth and Denver City Railway reached it in 1882. That rail link helped the county grow from about 5,000 people in 1880 to more than 17,000 by 1910. Cattle ranching and cotton farming drove the early economy. Cotton acreage peaked near 80,000 acres around 1930.
Oil was discovered near present-day Petrolia in 1901. The county produced over 204 million barrels of oil between 1917 and 2004, according to the TSHA Handbook of Texas. Today the population is roughly 10,000. Agriculture and livestock still anchor the economy.
Source to confirm: TSHA Handbook of Texas — Clay County