The following is a list of sources used in the creation of Wikipedia articles on various geographic topics and locations, such as cities, counties, states, and countries. These sources are cited within the thousands of articles which link to this page.

1 The United States Census Bureau's 2000 gazetteer. This was the primary source for the latitude and longitude values for about 23,500 U.S. cities. The data are indexed by state, county, and place FIPS codes.
Source: http://www.census.gov/geo/www/gazetteer/gazette.html
2 The United States Census Bureau's 2000 census data. Much of the geographic and demographic information for the U.S. states, counties, and cities came from the raw data on the site. The data are not totally accurate due to various polling errors, but they are a sufficient estimator. See the Bureau's website for more information. The data were used for the following topics: geographic areas (total, land, and water), population and housing unit densities, demographic spreads across race, age, sex, and income. The data are indexed by state, county, and place FIPS codes. See also Race (US Census) for a list of the definition of race according to the U.S. Census Bureau.
Source: http://factfinder.census.gov/servlet/BasicFactsServlet
3 The Geographic Names Information System developed by the United States Geological Survey. The data contain information on a wide range of geographic features such as populated places, rivers, mountains, certain buildings, etc. The data provided include geographic coordinates, elevation at the point, population (if applicable), and the FIPS codes for the state and county containing the feature (but not the feature itself).
Source: http://geonames.usgs.gov/
4 The FIPS55 database, which contains standardized codes for populated places in the United States. The system describes the codes and the relationships between different entities, such as the part of relationship between a U.S. state and a county. It also contains zip code information.
Source: http://geonames.usgs.gov/fips55.html
5 The National Imagery and Mapping Agency's (NIMA) database of foreign geographic feature names. Excludes information on the United States and Antarctica. Includes geographical coordinates in the WGS-84 format. Site also includes information on the FIPS10 standard.
Source: http://www.nima.mil/gns/html/index.html
6 A list of the U.S. county seats.
Source: http://www.campbellslist.com/county_seats/select_county_seat.html
7 The CIA World Factbook, which contains tables of miscellaneous facts about the countries of the world.
Source: http://www.cia.gov/cia/publications/factbook/
8 The U.S. Department of State website, which contains a variety of facts and statistics about countries of the world.
Source: http://www.state.gov/r/pa/ei/bgn/

Other sources

The following is a list of resources useful for a specific subset of the geographic topics. These resources can be used as a future source for additional information on that specific topic.