Qidong County is a county and the 8th most populous county-level division in the Province of Hunan, China; it is under the administration of Hengyang prefecture-level city. The county was formed from the eastern part of Qiyang County in April 1952 and was named after the east of Qiyang. Qidong County covers an area of 1,872 km2 (723 sq mi), and as of 2015, it had a registered population of 1,067,000. The county has four subdistricts, 17 towns and three townships under its jurisdiction, and the county seat is Hongqiao Subdistrict (洪桥街道).