Kitt Peak National Observatory, on Kitt Peak in the Quinlan Mountains within the Tohono O’odham Nation, became a major U.S. center for astronomy after its site was chosen in 1958 and dedicated in 1960. With more than twenty optical telescopes and two radio telescopes, it has been one of the Northern Hemisphere’s largest concentrations of astronomical instruments. Research there has advanced work on dark matter, cosmic distances, high-redshift galaxies, and the Boötes Void, and supported discoveries including methane ice on Pluto and the Kuiper belt object Varuna. Despite tensions over development and damage from the 2022 Contreras Fire, it continues its research and public outreach missions.