Sonora (Spanish pronunciation: [soˈnoɾa] (listen)), officially Free and Sovereign State of Sonora (Spanish: Estado Libre y Soberano de Sonora), is one of 32 states which comprise the Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo. Sonora is bordered by the states of Chihuahua to the east, Baja California to the northwest and Sinaloa to the south. To the north, it shares the U.S.–Mexico border primarily with the state of Arizona with a small length with New Mexico, and on the west has a significant share of the coastline of the Gulf of California. Sonora's natural geography is divided into three parts: the Sierra Madre Occidental in the east of the state; plains and rolling hills in the center; and the coast on the Gulf of California. It is primarily arid or semiarid deserts and grasslands, with only the highest elevations having sufficient rainfall to support other types of vegetation. Sonora is home to eight indigenous peoples, including the Mayo, the O’odham, the Yaqui, and Seri. The state has been economically important for its agriculture, livestock (especially beef), and mining since the colonial period, and for its status as a border state since the Mexican–American War. With the Gadsden Purchase, Sonora lost more than a quarter of its territory. From the 20th century to the present, industry, tourism, and agribusiness have dominated the economy, attracting migration from other parts of Mexico.