Neither Spain nor Mexico ever colonized the area beyond the southern and central coastal areas of present-day California and small areas of present-day Arizona, so they exerted no effective control in modern-day California north of the Sonoma area, or east of the California Coast Ranges. Most interior areas such as the Central Valley and the deserts of California remained in de facto possession of indigenous peoples until later in the Mexican era when more inland land grants were made, and especially after 1841 when overland immigrants from the United States began to settle inland areas.