This report examines the populations of metropolitan and micropolitan statistical areas of the United States, focusing on size, most populous areas, and fastest-growing areas, first for metropolitan statistical areas and then for micropolitan statistical areas.  

It uses U.S. Census Bureau population estimates and estimates of the components of population change (see Methodology and Sources of Data), which can interact in different ways in different areas. The population within an area can change due to natural increase (more births than deaths) or natural decrease (more deaths than births) or net migration, which is the sum of net domestic migration and net international migration. Rates for the components of change are expressed as annual rates per 1,000 population.