Trinidad is the home rule municipality that is the county seat and the most populous municipality of Las Animas County, Colorado, United States. The population was 8,329 as of the 2020 census. Trinidad lies 21 mi (34 km) north of Raton, New Mexico, and 195 mi (314 km) south of Denver. It is on the historic Santa Fe Trail.

The Colorado Fuel and Iron Company (CF&I) was a large steel conglomerate founded by the merger of previous business interests in 1892. By 1903 it was mainly owned and controlled by John D. Rockefeller and Jay Gould's financial heirs. While it came to control many plants throughout the country, its main plant was a steel mill on the south side of Pueblo, Colorado, and was the city's main industry for most of its history. From 1901 to 1912, Colorado Fuel and Iron was one of the Dow Jones Industrials. The steel-market crash of 1982 led to the decline of the company. After going through several bankruptcies, the company was acquired by Oregon Steel Mills in 1993, and changed its name to Rocky Mountain Steel Mills. In January 2007, Rocky Mountain Steel Mills, along with the rest of Oregon Steel's holdings, were acquired by EVRAZ Group, a Russian steel corporation, for $2.3 billion.