Demographic basics, Boulder County

Boulder County had a total of 31,680 residents in 1920. They came from 35 different countries in addition to the United States and spoke 30 different languages; the most common (besides English) were German and Swedish (see Figure 1.) By far the largest group was those born in Colorado (perhaps because the age distribution skewed toward children, see Figure 1), but almost 13 percent were born overseas and a slightly higher percentage had parents who were born overseas (see Table 1.)

Nativity Percent
Foreign born 12.44%
Native born, and both parents foreign 14.48%
Native born, and both parents native born 64.16%
Native born, and father foreign, mother native 6.26%
Native born, and mother foreign, father native 2.66%
Total 100.00%

Table 1. Nativity of Boulder County residents, 1920


Age distribution showing bottom of pyramid is broad

Figure 1. Age distribution in Boulder County, 1920.

Most common mother tongues

Figure 2. Most common mother tongues, Boulder County, 1920.


The population of Boulder County was about half rural and half urban, but there was a fair bit of variation in who lived where. Despite the common perception of early-twentieth-century immigrants as heavily concentrated in urban environments, in Boulder County the native-born population was nearly two thirds urban, while the immigrant population was about two thirds rural (69 percent for the foreign born, 65 percent for the second generation.) As we can see in Figure 2, some immigrant groups, like Austrians, Belgians, Bulgarians, and Japanese, were almost entirely concentrated in rural places, while others were half or more urban (Canadians, Irish, Norwegians, Danes.)

Figure 3. Urban vs. rural population by place of birth.