El Paso County is the most populous county located in the American state of Colorado. As of the 2020 Census, the population was 730,395, surpassing the City and County of Denver. The county seat is Colorado Springs, the second most populous city in Colorado. El Paso County is included in the Colorado Springs, Colorado, Metropolitan Statistical A…El Paso County is the most populous county located in the American state of Colorado. As of the 2020 Census, the population was 730,395, surpassing the City and County of Denver. The county seat is Colorado Springs, the second most populous city in Colorado. El Paso County is included in the Colorado Springs, Colorado, Metropolitan Statistical Area.