Geography

Countries:

CIA World Fact Book (Facts about any country in the world)

Infoplease Almanac 

BBC's Country Profiles

Lonely Planet Worldguide 

Library of Congress Country Profiles 

Travel.State.Gov (U.S. Dept. of State)

Culture for Kids (introduction to eleven countries across the globe)

National Geographic Online Geography Games(Includes GeoBee)

GeoNet (Test your knowledge by playing a geography game) 

Owl & Mouse (Interactive Map puzzles)

Population Reference Bureau (Population data for U.S. and other countries)


States:

The 50 States of the United States

Infoplease.com 

Stately Knowledge: Facts about the United States

The US50, Inc. 

GeoNet (Test your knowledge by playing a geography game) 

*In addition to these web sites, each state has its official Web site that can be found using the following formula: http://www.state.(postal abbreviation).us

Owl & Mouse (Interactive Map puzzles)

Bureau of Labor Statistics (U.S. Dept. of Labor)

U.S. Census Bureau