Sinaloa, officially Free and Sovereign State of Sinaloa, is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 18 municipalities and its capital city is Culiacán Rosales.
It is located in Northwestern Mexico. It 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 has a significant share of coastline on 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.
Prior to the coming of the Spaniards, much of Sinaloa was inhabited by the Cáhita.
In 1531 Nuño Beltrán de Guzmán with a force of over 10,000 defeated a force of 30,000 Cáhita at the site of Culiacan. Beltran de Guzman established a Spanish and allied Indian outpost at Culiacan. Over the next decade, the Cáhita suffered severe depopulation from smallpox and other diseases the Spanish brought.
The Spanish organized Sinaloa as part of the gobierno of Nueva Galicia. In 1564, the area was realigned, with the area of Culiacan and Cosala remaining in the control of Nueva Galicia, while the areas to the north, south and west were put in the newly formed Nueva Vizcaya, making the Culiacan area an exclave of Nueva Galicia. The first capital of Nueva Vizcaya was located in San Sebastian, Sinaloa, near Copala, but the capital moved to Durango, 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. In 1601, the Jesuits' movement into the eastern part of Sinaloa led to the Acaxee going to war. The Spanish eventually managed to reassert authority in the Sierra Madre and executed 48 Acaxee leaders.
After Mexican independence, Sinaloa was joined with Sonora as Occidente State, but it became a separate state in 1830.