Colt is a Second Class City in St. Francis County, Arkansas, United States. The population was 378 at the 2010 census, an increase fro…Colt is a Second Class City in St. Francis County, Arkansas, United States. The population was 378 at the 2010 census, an increase from 368 in 2000. According to the United States Census Bureau, the city has a total area of 1.2 square miles, all land.