The national observatories of the United States, which are funded primarily by the U.S. National Science Foundation, are the National Optical Astronomy Observatory (NOAO) and the National Radio Astronomy Observatory (NRAO). NOAO and NRAO both operate several facilities. NOAO has the National Solar Observatory; Kitt Peak «, National Observatory in southern Arizona; Cerro Tololo Inter-American Observatory near La Serena, Chile; and the NOAO Gemini Science Center, which is responsible for one telescope on Cerro Pachon, Chile, and another on Mauna Kea, Hawaii. NOAO’s main scientific office is in Tucson, Arizona. NRAO has the Very Large Array near Socorro, New Mexico; the Green Bank Radio Observatory at Green Bank, West Virginia; the Very Long Baseline Array (VLBA) which spans more than five thousand miles; and the Atacama Large Millimeter Array (ALMA) in the Chajnantor plain of the Atacama Desert in northern Chile. NRAO’s main office is in Charlottesville, Virginia.