El Paso County is the most populous of the 64 counties of the state of Colorado of the United States. The U.S. Census Bureau reported that the county population was 622,263 in 2010, greater than Denver County, which had previously been the most populous county. The county seat of El Paso County is Colorado Springs, the second most populous city in Colorado. The Colorado Springs Metropolitan Statistical Area comprises El Paso County and Teller County.
El Paso County is located in Colorado's 5th congressional district. Since its creation in 1871, El Paso County has typically voted for the Republican presidential candidate in presidential elections; the last Democratic nominee to win the county was Lyndon B. Johnson in 1964. The Democratic Party won El Paso County four additional times prior, and the Populist Party won in 1892, with General James B. Weaver.
In 2004, the voters of Colorado Springs and El Paso County established the Pikes Peak Rural Transportation Authority (PPRTA) and adopted a 1% sales tax dedicated to improving the region's transportation infrastructure. Together with state funding for COSMIX (2007 completion) and the I-25 interchange with Highway 16 (2008 completion), significant progress has been made since 2003 in addressing the transportation needs of the area.
In July 1858, gold was discovered along the South Platte River in Arapahoe County, Kansas Territory. This discovery precipitated the Pike's Peak Gold Rush. Many residents of the mining region felt disconnected from the remote territorial governments of Kansas and Nebraska, so they voted to form their own Territory of Jefferson on 1859-10-24. The following month, the Jefferson Territorial Legislature organized 12 counties for the new territory including El Paso County. El Paso County was named for the Spanish language name for Ute Pass north of Pikes Peak. Colorado City served as the county seat of El Paso County.
The Jefferson Territory never received federal sanction, but on 1861-02-28, U.S. President James Buchanan signed an act organizing the Territory of Colorado. El Paso County was one of the original 17 counties created by the Colorado legislature on November 1, 1861. Part of its western territory was broken off to create Teller County in 1899. Originally based in Old Colorado City (now part of Colorado Springs, not today's Colorado City between Pueblo and Walsenburg), El Paso County's county seat was moved to Colorado Springs in 1873.