Zebra duiker (Cephalophus zebra). Dallas–Fort Worth. • Water (%). Los Angeles. 3,796,742 sq mi (9,833,520 km2)[9] (3rd[c]). 2021 MSA population estimates from the U.S. Census Bureau. • Total area. Religious affiliation in the United States is among the most diverse in the world[430] and varies significantly by region[431] and age.