Sinaloa (sinaˈloa), officially the Estado Libre y Soberano de Sinaloa (Free and Sovereign State of Sinaloa), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. It is divided into 18 municipalities and its capital city is Culiacán Rosales.
It is located in northwest Mexico, and is bordered by the states of Sonora to the north, Chihuahua and Durango to the east (separated from them by the Sierra Madre Occidental) and Nayarit to the south. To the west, Sinaloa faces Baja California Sur across the Gulf of California. The state covers an area of , and includes the Islands of Palmito Verde, Palmito de la Virgen, Altamura, Santa María, Saliaca, Macapule and San Ignacio. In addition to the capital city, the state's important cities include Mazatlán and Los Mochis.
Sinaloa belongs to the northern limit of Mesoamerica. From the Fuerte River to the north is the region known as Aridoamerica, which includes the desert and arid places of northern Mexico. Before European contact, the territory of Sinaloa was inhabited by groups such as the Cahitas, the Tahues, the Acaxees, the Xiximes, the Totorames, the Achires and the Guasaves.
In 1531, Nuño Beltrán de Guzmán, with a force of over 10,000 men, established a Spanish and allied Indian outpost at San Miguel de Culiacán. Over the next decade, the Cahíta suffered severe depopulation from conquest, smallpox and other diseases brought by Europeans.
The Spanish organized Sinaloa as part of the gobierno of Nueva Galicia. In 1564, the area was realigned: the area of Culiacán and Cosalá remained in control of Nueva Galicia, while the areas to the north, south and west were made part of the newly formed Nueva Vizcaya province, making the Culiacán area an exclave of Nueva Galicia. The first capital of Nueva Vizcaya was located in San Sebastián, near Copala, but was moved to Durango in 1583.
Starting in 1599, Jesuit missionaries spread out from a base at what is now Sinaloa de Leyva and by 1610, the Spanish influence had been extended to the northern edge of Sinaloa.