Murdo is a city in Jones County, South Dakota, United States. The population was 488 at the 2010 census. It is the county seat of Jones County. Murdo is named for Murdo MacKenzie, a Texas cattleman, and was the hometown of current Republican U.S. Senator John Thune. According to the United States Census Bureau, the city has a total area of 0.63 square miles (1.63 km2), all of it land.