查尔斯米克斯县（Charles Mix County, South Dakota）是美国南达科他州东南部的一个县，西、南界密苏里河，南与内布拉斯加州相望。面积2,979平方公里。根据美国2000年人口普查，共有人口9,350人。县治莱克安第斯（Lake Andes）。

成立于1862年5月8日，1864年解散，1879年重建。县名纪念印第安人治安官、军人查尔斯·H·米克斯。

Charles Mix County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 9,129. Its county seat is Lake Andes. The county was created in 1862 and organized in 1879. It was named after Charles Eli Mix, an official of the Bureau of Indian Affairs influential in signing a peace treaty with the local Lakota Indian tribes. The easternmost approximately 60% of the county comprises the Yankton Indian Reservation.