The town was named after Horace Greeley, editor of the New-York Tribune, who came to Colorado in the 1859 Pike's Peak Gold Rush. It was founded as the Union Colony in 1869, an experimental utopian society, but the name was later changed in honor of Horace Greeley. Governor Benjamin Harrison Eaton declared Greeley an official city on April 6, 1886.
Greeley was built on farming and agriculture but kept up with most modern technologies as they grew. Telephones were in town by 1883 with electric lights downtown by 1886. Automobiles were on the roads alongside horse drawn buggies by 1910. KFKA became one of the first radio stations to broadcast in the USA in 1922 and the Greeley Municipal Airport was built in 1928. Greeley housed two POW camps in 1943, during World War II. One was for German POWs and the other was for Italian POWs. A vote to allow the sale of alcohol passed by a mere 477 votes in 1969, thus ending Temperance in the city.