A gazetteer is a geographic dictionary index; a combination atlas and almanac. For example, a gazetteer of a county would name and describe all of the towns, lakes, rivers, and mountains in the county.
Regular Websites
Alexandria Digital Library Gazetteer Server
A gazetteer of the world containing about 6,000,000 entries. Searchable by place name and feature type (anticlines, aqueducts, archaeological sites, etc.) and browsable by map. Results are displayed on a map providing longitude, latitude, elevation, and related information. From the University of California, Santa Barbara. - Alexandria Digital Library Gazetteer Server
http://www.alexandria.ucsb.edu/gazetteer/
Contains details of towns, villages, bens and glens from the Scottish Borders to the Northern Isles. Also includes tourist attractions, industries and historical sites, histories of family names and biographies of famous people associated with Scotland. Searchable, and browsable by map, and timeline. - Gazetteer for Scotland
http://www.geo.ed.ac.uk/scotgaz/
Geographic Names Information System (GNIS)
This database allows the user to query nearly two million geographic names by feature name, state or territory, elevation, and topographic map name. From the U.S. Geological Survey (USGS). - Geographic Names Information System (GNIS)
http://geonames.usgs.gov/pls/gnispublic/f?p=135:1:16155290222503193126
Authoritative source of over 500,000 geographical names in Canada. Search by geographical name, point coordinates, or CGNDB Unique Identifer. Results show basic locational information and maps. Available in English and French. Maintained by the Canadian Permanent Committee on Geographical Names (CPCGN). - Geographical Names of Canada
http://geonames.nrcan.gc.ca/
This website attempts to list all online government gazettes and their characteristics to aid researchers. A description of the contents and coverage are included for each gazette. From the University of Michigan School of Information. - Government Gazettes Online
http://www.lib.umich.edu/govdocs/gazettes/
Key Names: A Gazetteer of the Islands of the Florida Keys
An annotated compilation of every place name for the islands and keys (low islands or reefs) in Florida. The search function is really just a sophisticated browse, though it works well enough. Includes a brief glossary. - Key Names: A Gazetteer of the Islands of the Florida Keys
http://keys.fiu.edu/gazetteer/
Searchable database, by name or state abbreviation, or 5-digit zip code. Contains geographic information, maps and census data. - U.S. Gazetteer
http://www.census.gov/cgi-bin/gazetteer
USGS Geographic Names Information System (GNIS)
Detailed information about a specific places or points of interest in the US, territories, and Antarctica. Includes elevation, description, population, historic notes, variant names, and USGS 7.5' map names. Search by feature name, County, State, or feature type. From the US Geological Survey. - USGS Geographic Names Information System (GNIS)
http://geonames.usgs.gov/