This report examines the population dynamics of the Great Plains in the period from 1950 to 2007. Analysis for 1950 to 2000 uses decennial census data; for 2007, the data are from the Census Bureau’s Population Estimates Program. Based on patterns of county-level population growth and decline, the report analyzes the demographic components of population change to establish which demographic events (births, deaths, or migration) most strongly affected the population changes.