Kitt Peak is the oldest national observatory in the United States. It was founded in 1958, when the National Science Foundation signed a lease with the Tohono O’odham Nation, upon whose land the observatory resides.
Before Kitt Peak, observatories were either privately funded, such as Lowell Observatory, founded by Percival Lowell, or university managed, such as the Harvard College Observatory. But with the rise of the Cold War in the 1950s, there was a desire to have an American space program, which would be supplemented by a national astronomy program. Kitt Peak was chosen as the location because of its high altitude and clear calm skies. It was also reasonably close to the University of Arizona, which had (and still has) an excellent astronomy program.
Over the years some of Kitt Peak’s status as the flagship U.S. observatory has faded a bit as newer and larger telescopes have been built elsewhere, the history of Kitt Peak is still evident its wide range of telescopes. There are optical telescopes ranging in size from 0.9 meters to the 4-meter Mayall telescope. There are radio telescopes, including a 25-meter telescope that is part of the Very Long Baseline Array, and there is even the McMath-Pierce solar observatory, which observes the Sun during daylight hours.
If you are ever in the area, the observatory does have daily tours and night viewing sessions. It’s one of the more accessible major observatories, and well worth the visit.