Colorado Fuel & Iron, under the guidance of first John D. Rockefeller and then his son John D. Rockefeller Jr., greatly expanded in the southern Colorado coalfields in the decade following their 1903 investment in the company. Among these expansions was the construction of the Valdez mine in 1907. Soon after its creation, the mine was renamed to "Frederick" and rapidly expanded, producing bituminous coal sent to the coking ovens at Segundo. Frederick coal was also, from 1918 onwards, shipped towards the CF&I Minnequa steel mill along the Colorado and Wyoming Railway, part of the company's vertical integration strategy. During this early period, Apache Indians reportedly frequented the town and surrounding area.
Founding dates: Wikidata, Wikipedia, the U.S. post office records of Blevins & Helbock (CC0) and the Census. Homes by year built: Census ACS 2020–24. National Register of Historic Places: National Park Service (list of May 22, 2026). Old photos, postcards and papers: Wikimedia Commons, the Library of Congress and other public archives, credited on each item’s page. Maps: U.S. Geological Survey historical topographic maps (via Esri) and Sanborn fire-insurance maps (Library of Congress). History text and census tables: Wikipedia (CC BY-SA 4.0). Places that used to be: USGS Geographic Names Information System (2021). How TownRatings grades history →
From Wikipedia, U.S. Geological Survey historical maps, the US Post Offices dataset (Blevins & Helbock) and the USGS Geographic Names Information System. Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.