Eldora (pronounced el-DOH-ruh),[5] previously known as "Eldorado" then "El-Dora", then Eldora or Camp Eldorado, and still called Happy Valley,[6][7][8] is an unincorporated community and a census-designated place (CDP) located in and governed by Boulder County, Colorado, United States.

Eldora is tucked into the valley carved by glaciation during the last ice age and by Middle Boulder Creek.

[15] The area is home to an abundance of wilderness and wildlife, including animals such as mountain lions, black bears, coyotes, red foxes, mule deer, elk, bobcats, and much more.

Postal Service mistakenly delivered their mail to towns by the same name in other U.S. states, particularly to El Dorado, CA,[18][19] creating havoc by delaying payroll checks and important papers.

[7] That name change occurred in 1898, one year after the local post office was established (Feb. 13, 1897), which was in use until it closed in September 1977.

In 1898, Eldora was home to a bank, a post office, a school, nine hair saloons and seven grocery stores.

Eldora is located within the Roosevelt National Forest, at the base of Ute Mountains in the Middle Boulder Creek valley.