Mar 17, 2026 - News
1 map: Irish ancestry in Colorado
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11% of Colorado's population identifies as Irish, the latest census numbers show.
Why it matters: Today's St. Patrick's Day, so let's raise a Guinness to our Irish neighbors.
State of play: About 657,000 Colorado residents report Irish ancestry, and it's no surprise given the state's history.
- Irish immigrants worked in Colorado's mines dating back to the 1850s and their population bloomed in the 1870s when silver was discovered in Leadville, the Denver Public Library's research shows.
Fun fact: In the 1880 census, nearly 5,000 Irish-Americans and Irish-born immigrants lived in Lake County, where Leadville is located.
- Now, the largest proportion of Irish ancestors live in Mineral (18%), Clear Creek (17.7%) and Gilpin (16.5%) counties.
Zoom in: Boulder County is at 12.65%, 21st in the state.
🗯️ Mitchell's thought bubble: I'm supposedly 1/8 Irish on my dad's side. Enough that I like Guiness, but not enough that I eat Irish food or dance.