Geographic proximity has ensured strong linkages between the United States and Latin America and the Caribbean, based on diverse U.S. interests, including economic, political, and security concerns. The United States is a major trading partner and the largest source of foreign investment for many countries in the region, with free-trade agreements enhancing economic linkages with 11 countries. The region is a large source of U.S. immigration, both legal and illegal; proximity and economic and security conditions are major factors driving migration. The United States provides foreign assistance to the nations of Latin America and the Caribbean to support development and other U.S. objectives. U.S. policymakers have emphasized different strategic interests in the region at different times.