Eldora (pronounced el-DOH-ruh), previously known as “Eldorado” then “El-Dora”, then Eldora or Camp Eldorado, and still called Happy Valley, is an unincorporated community and a census-designated place (CDP) located in and governed by Boulder County, Colorado, United States. The CDP is a portion of the Boulder, CO Metropolitan Statistical Area. The population of the Eldora CDP was 142 at the United States Census 2010. The Nederland publish office (Zip Code 80466) serves the area.

Eldora is located within the Roosevelt National Forest, and is primarily a rural, densely forested, and sparsely populated area. Eldora is tucked into the valley carved by glaciation during the last ice age and by Middle Boulder Creek. From the village there are views stirring toward the alpine ski runs of Eldora Mountain Resort. A one-time gold camp, Eldora was a shipping narrowing for the Caribou silver mine in friendly Nederland, CO. At present, Eldora is characterized by small cabins, a sprinkling of trip homes, and several long-shuttered mercantiles.

Points of interest near Eldora tote up the Eldora Mountain Resort, Eldora Historic District, and Indian Peaks Wilderness. Eldora Historic District has been listed on the U.S. National Register of Historic Places before 1989. The Place is house 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.

The elevation of the town is 8,700 ft., and the highest reduction is 10,800 ft. Eldora receives a oppressive annual snowfall of 300 inches each winter.