Prior to redistricting the district was represented by Republicans Jerry Sonnenberg and Greg Brophy.

[3][4] District 1 covers much of the Eastern Plains in the state's northeastern corner, including all of Cheyenne, Elbert, Kit Carson, Lincoln, Logan, Morgan, Phillips, Sedgwick, Washington, and Yuma Counties and parts of Weld County.

Communities in the district include Julesburg, Holyoke, Sterling, Brush, Fort Morgan, Eaton, Kersey, Lochbuie, Hudson, Keenesburg, Ault, Akron, Wray, Yuma, Burlington, Limon, Elizabeth, Ponderosa Park, and Cheyenne Wells.

[1] Colorado state senators are elected to staggered four-year terms; under normal circumstances, the 1st district holds elections in midterm years.

The 2022 election is the first held under the state's new district lines.