Juan Bautista de Anza made an exploratory expedition to Alta California in 1774, then was sent again to take colonist families with him. As the expedition moved north, he recruited them in Culiacán, Guasave, and Horcasitas, which were among the only principal towns of the internal northwest (today's Sinaloa and Sonora).
The trip across the desert is reasonably well documented with three diaries surviving (those of Anza, Font, and Garcés, all of which are published at "Web de Anza"). However, those diaries all begin much farther north. The main part of the expedition got going after its stop in October of 1775 at the Presidio of Tubac, today in Arizona.
So when in 1775 was Anza's recruitment stop in Culiacán? I can accept circumstantial evidence or a range of possible dates.