Coolidge is a city in Pinal County, Arizona, United States. According to 2005 Census Bureau estimates, the population of the city is 8,154. Arizona Highway 87 and Arizona Highway 287 pass through the town. Coolidge is 56 miles southeast of Phoenix, and 69 miles northwest of Tucson. It is 21 miles northeast of Casa Grande and 11 miles southwest of Florence. Picacho Reservoir is just 11 miles south of town. Coolidge is home of the Casa Grande Ruins National Monument.