[3] The county is named for Alva Adams, an early Governor of the State of Colorado in 1887–1889.

Jack Henderson eventually returned to eastern Kansas and fought for the Union in the American Civil War.

Henderson Island is today the site of the Adams County Regional Park and Fairgrounds.

A ruling by the Colorado Supreme Court, subsequent legislation, and a referendum delayed the creation of Adams County until November 15, 1902.

Governor James Bradley Orman designated Brighton as the temporary Adams County Seat.

Adams County originally stretched 160 miles (260 kilometers) from present-day Sheridan Boulevard to the Kansas state border.

There are five members that form the Board of Commissioners with each elected to represent a district or portion of the county.

[16] Adams County is predominately Democratic, not having voted Republican since Ronald Reagan in 1984.

The school districts serving Adams County are:[18] The county is also home to the Westminster campus of Front Range Community College, the largest community college by enrollment in Colorado.

Up until 1999 when Colorado ceased coding license plates by county, Adams County used the following codes on license plates issued to passenger vehicles: TE-UF, GA-GG, SAA-SEW, and SEY-TZZ.