The following outline is provided as an overview of and topical guide to the U.S. state of Colorado:
Colorado - 22nd most populous, the eighth most extensive, and the highest in average elevation of the 50 United States. Colorado is one of the western Mountain States. The 30 highest major summits of the Rocky Mountains all rise within Colorado. The Territory of Colorado joined the Union as the 38th state on August 1, 1876.