In 1810, Mexico declared its independence from Spain, and the Sierra Estrellas went on to become part of Mexico. In 1827, a French fur trapping expedition led by Michel Robidoux was attacked by Indians (O'odham?) and survivors escaped into the Sierra Estrella mountains. In 1853, the United States acquired the Estrellas from Mexico as part of the Gadsden purchase. It soon became part of a trade route for settlers in California known as the Butterfield Overland stage. People and equipment could be moved across the area much quicker. The route was massively successful its time, moving millions of dollars in supplies. However, it was short-lived. Steam locomotives soon replaced stage coaches across the United States, and the Butterfield Stage Route was no longer utilized.