The history of Arapahoe County, Colorado is a long and varied one. After the Colorado Gold Rush, agriculture and ranching were the mainstays of the eastern part of the county, while cities continued to develop around Denver. In 1832, the first South Platte River trading post was built in Cherry Creek, then part of Arapahoe County. After the admission of Kansas in 1861, Arapahoe County was resized and named one of the first seventeen counties in the new Colorado Territory.
In 1959, the 18th Judicial District was created and Arapahoe County was included in the new district, along with Douglas, Elbert, and Lincoln counties. Denver became the seat of Arapahoe County, and remained so until 1902, when the county was divided into several counties that today make up the Denver metropolitan area. After the discovery of gold along Dry Creek in 1858, a continuous flow of immigrants from the east led to the creation of new counties, and Arapahoe County was gradually reduced to its current size. At first, Littleton was considered to be the temporary county seat; an election in 1904 made it the permanent seat of the new Arapahoe County.
Although the Arapaho and their allies continued their sporadic incursions during the 1870s, by the end of the 19th century, Arapahoe County had been practically free of the population that gave it its name. In 1959, the 18th Judicial District was created and Arapahoe County was included in the new district. In 1959, before the formal founding of the Arapahoe County Bar Association (ACBA), a group of lawyers from Arapahoe County decided to meet to explore forming a bar association independent from that of the 1st Judicial District. The ACBA is proud to have been a major contributor to constructing the new Arapahoe County Justice Center which opened in 1989. As their communities grew, residents of Arapahoe County also realized that they would have to decide whether they wanted to join Denver or remain independent.
After winning a court battle against Denver's attempt to annex property in Arapahoe County, residents chose to remain independent. The ACBA has since been involved in public education projects in local high schools; it has provided volunteers for Help Center 4 AskLawyer program and it has helped with Colorado Bar Association's high school mock trial program. Today, Arapahoe County covers 805 square miles in north-central Colorado and extends east across the high plains from Denver's southern tip. The county has seen many changes over time but remains an integral part of Colorado's history.
