Colorado's 21st Senate district is one of 35 districts in the Colorado Senate. It is represented by represented by Democrat Adrienne Benavidez who was selected by a vacancy committee in February 2026 to succeed Democrat Dafna Michaelson Jenet.
District 21 covers the immediate northern suburbs of Denver in Adams County, including Commerce City, Federal Heights, Berkley, Derby, Sherrelwood, Twin Lakes, Welby, parts of Shaw Heights and Westminster, and the eastern tip of Arvada.
The district is located entirely within Colorado's 7th congressional district, and overlaps with the 30th, 31st, 32nd, 34th, and 35th districts of the Colorado House of Representatives.
Colorado state senators are elected to staggered four-year terms; under normal circumstances, the 21st district holds elections in presidential years.