Delta County is the name of several counties in the United States:
Delta County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 5,231. Its county seat and largest city is Cooper. The county was founded in 1870 and is named for its triangular shape, much like the Greek letter delta.
Two forks of the Sulphur River form its northern and southern boundaries, and meet at its easternmost point. Delta County is one of 19 prohibition, or entirely dry, counties in the state of Texas. As of 2015, Delta county is no longer a dry county.
Delta County is represented in the Texas House of Representatives by Republican Larry Phillips of Sherman, Texas.
According to the U.S. Census Bureau, the county has a total area of 278 square miles (720 km2), of which 257 square miles (670 km2) is land and 21 square miles (54 km2) (7.6%) is water.