Diamond City is a hamlet in southern Alberta, Canada within the Lethbridge County. It is located on Highway 25, approximately 13 kilometres (8.1 mi) north of Lethbridge. The community was so named on account of deposits of coal near the original town site, a resource also called "black diamond". Diamond City was first settled at the turn of the 20th century by farmers, ranchers and miners. The community grew rapidly when a coal mine was opened in 1905. Previously an incorporated town, Diamond City dissolved on June 30, 1937.