Russia had fur-trading interests in Alaska, and wanted to search for furs farther south along the Pacific Coast. In 1812, the Russians established Fort Ross on the northern California coast. Russian activity in California was one reason for the Monroe Doctrine, proclaimed in 1823. In the Monroe Doctrine, the United States declared that North and South America should be considered closed to European colonization. In 1824, Russia agreed to limit its settlements to Alaska. However, the Russians did not actually leave the California region until the early 1840's.