 On November 8, 1904, Adams County voters chose Brighton as the permanent county seat.A 1989 vote transferred 53 square miles (137 square kilometers) of Adams County to the City and County of Denver for the proposed Denver International Airport, leaving the densely populated western portion of the county as two oddly-shaped peninsulas.Adams County lost the tip of its northwest corner when the consolidated City and County of Broomfield was created on November 15, 2001.