Douglas is a city in Cochise County, Arizona, United States that lies in the north-west to south-east running Sulpher Springs Valley. Douglas has a border crossing with Mexico at Agua Prieta and a history of mining.
The population was 17,378 at the 2010 census.
The Douglas area was first settled by the Spanish in the 18th century. Presidio de San Bernardino was established in 1776 and abandoned in 1780. It was located a few miles east of present-day Douglas. The United States Army established Camp San Bernardino in the latter half of the 19th century near the presidio, and in 1910 Camp Douglas was built next to the town.
Douglas was founded as an American smelter town, to treat the copper ores of nearby Bisbee, Arizona. The town is named after mining pioneer Dr. James Douglas and was incorporated in 1905. Two copper smelters operated at the site.