Frederick is a Statutory Town in Weld County, Colorado, United States. The population was 8,709 at the 2010 census.
Initially named McKissick for the mine owner, Frederick was renamed when the daughters of Frederick A. Clark, a land owner, laid out the town site in 1907 and named it for their father. Incorporated in 1907, the Town of Frederick began as a coal mining town attracting immigrants from Italy, France, Greece, Turkey, several Slavic countries and Latin America. The Frederick Coal mine closed in 1928.
In 2014 the town 're-branded' by designing a logo that is a stylized gas lamp with a mountain range background, and adopting the tag line "Built on What Matters". Prior to the re-branding the town primarily used the seal as a logo on town vehicles and letter head.
The city gained international attention in 2018 when it became the location of the widely publicized Watts family murders.
Frederick is located at 40°6′40″N 104°57′39″W (40.111175, −104.960967).
According to the United States Census Bureau, the town has a total area of 8.7 square miles (23 km2), of which, 8.6 square miles (22 km2) of it is land and 0.1 square miles (0.26 km2) of it (1.03%) is water.
Immediately adjacent communities to Frederick are Firestone to the North, and Dacono to the South. Frederick, Firestone, and Dacono generally being called the 'Tri-Towns' or the 'Tri-Town area', the area in general being called 'Carbon Valley'. The next closest communities are Erie to the southwest, Longmont to the west, Fort Lupton to the east, and an unincorporated area of Weld County called DelCamino to the northwest.