Focusing on a population’s age and sex composition is one of the most basic ways to understand population change over time. Since Census 2000, the population has continued to grow older, with many states reaching a median age over 40 years. At the same time, increases in the number of men at older ages are apparent. Understanding a population’s age and sex composition yields insights into changing phenomena and highlights future social and economic challenges.

This report describes the age and sex composition of the United States in 2010. It is part of a series that provides an overview of the population and housing data collected from the 2010 Census. It highlights analysis of age and sex at the national level, as well as for regions, states, and counties and for places with populations of 100,000 or more. A comparison with Census 2000 data is also provided, showing the changes in age and sex composition that have taken place over the last 10 years.

This report also provides information about how age and sex data were collected in the 2010 Census. The data for this report are based on the 2010 Census Summary File 1, which is among the first 2010 Census data products to be released.