Eldorado Springs, Colorado  Eldorado Springs is a census-designated place (CDP) in Boulder County, Colorado, United States. The population was 585 at the 2010 census. The Eldorado Springs Post Office has the ZIP Code 80025. In 1910, Eldorado Springs was a resort community, known for its Big Radium Pool, then the largest swimming pool in the United States. The pool, along with several other smaller ones, was known as "Coney Island of the West." In 1916, Dwight and Mamie Eisenhower celebrated their honeymoon in one of the cabins at the resort. Also known for its good tasting spring water, "Eldorado Springs" bottled water is sold in stores around Colorado. The nearby Eldorado Canyon State Park is famous for its classic North-American climbing routes. Eldorado Springs is located at (39.940786, -105.255930). According to the United States Census Bureau, the CDP has a total area of , all of it land. To the southwest is Eldorado Mountain. As of the census of 2000, there were 557 people, 275 households, and 133 families residing in the CDP. The population density was 232.1 people per square mile (89.6/km²). There were 295 housing units at an average density of 122.9 per square mile (47.5/km²). The racial makeup of the CDP was 94.61% White, 0.72% African American, 0.18% Native American, 1.80% Asian, 0.90% from other races, and 1.80% from two or more races. Hispanic or Latino of any race were 2.87% of the population. There were 275 households out of which 20.0% had children under the age of 18 living with them, 39.3% were married couples living together, 5.5% had a female householder with no husband present, and 51.6% were non-families. 38.5% of all households were made up of individuals and 2.9% had someone living alone who was 65 years of age or older. The average household size was 2.03 and the average family size was 2.74. In the CDP, the population was spread out with 17.2% under the age of 18, 5.6% from 18 to 24, 35.5% from 25 to 44, 33.8% from 45 to 64, and 7.9% who were 65 years of age or older.