Government
Government Information on the Internet
All sorts of statistics related to the United States population can be found here. The middle of the page provides links to major areas of the site. More links -- to areas such as new material, publications and special features are on the left. The right side shows up-to-the-minute estimates of United States and world populations. It also has a box that lets you go to quick facts about any state.
Statistical Abstract of the United States
More information from the Census Bureau is available here. You'll find links to items such as USA Statistics in Brief and a Guide to State Statistical Abstracts. Other links take you to information about states, cities and counties in the United States.