Las Cruces is a city in Doña Ana County, New Mexico, and is the second largest city in the state. Las Cruces is the center of an agricultural region irrigated by the Rio Grande, which flows just west of the city. The city of Las Cruces bisects the fertile Mesilla Valley, the flood plain of the Rio Grande which extends from Hatch, New Mexico to the west side of El Paso, Texas. Las Cruces is also the home of New Mexico State University. NMSU is New Mexico's only land grant university, citing more than 30,000 graduate and undergraduate students on the main campus and four branch campuses. The Organ Mountains are to the east of the city. Las Cruces has a council-manager form of government. It is the county seat of Doña Ana County.