On January 5, 1859, George A. Jackson discovered placer gold at the present site of Idaho Springs where Chicago Creek empties into Clear Creek. It was the first substantial gold discovery in Colorado. Jackson, a Missouri native with experience in the California gold fields, was drawn to the area by clouds of steam rising from some nearby hot springs. Jackson kept his find secret for several months, but after he paid for some supplies with gold dust, others rushed to Jackson’s diggings.

The settlement was first called Spanish Bar, later renamed Idaho Springs, after the hot springs.

There were 143 households out of which 28.0% had children under the age of 18 living with them, 55.9% were married couples living together, 10.5% had a female householder with no husband present, and 28.7% were non-families. 20.3% of all households were made up of individuals and 4.2% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 2.98.

In the CDP the population was spread out with 25.0% under the age of 18, 7.7% from 18 to 24, 30.5% from 25 to 44, 29.9% from 45 to 64, and 6.9% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 119.3 males. For every 100 females age 18 and over, there were 118.4 males.