Geonames is an open source geographical database maintained by the Open Geospatial Consortium. It gathers data from several sources, such as government agencies and private companies, and creates a global dataset that can be used for a variety of applications. It contains information about the geography of any location and specifics about the location, like names, population data, area measurements, and more. It is a database of more than 10 million geographical names and features, including populated places like cities, towns, and villages, as well as natural features like mountains, islands, and water bodies. It also includes historical features like old cities and war-time camps, and more recent landmarks like border crossings and skywalks. Geonames provides comprehensive topical and geographic coverage and is one of the most comprehensive sources of geographic information available.

Geonames features include:

- Toponyms - Place names used to describe a location
- GPS Coordinates - Latitude and longitude coordinates for each location
- Administrative Regions - Country, province, and prefecture information for each location
- Population Data - Population estimates for most populated places
- Climate Data - Average temperature and rainfall trends for each location
- Time Zone - Local time zone information for each location
- Maps - Interactive, embeddable maps displayed along with each location

Given its comprehensive coverage, Geonames is widely used for a variety of purposes. For example, it is frequently used for geolocation services and geocoding websites, as well as being a key source of geographic reference data for GIS (Geographic Information System) applications and products. It is also used as an authoritative source of geographic information by numerous organizations, including UN agencies, government departments, non-profits, universities, and more.