Castlemap is a free interactive map showcasing 2,435 castles, fortresses, and palaces across 129 countries. Users can pan and zoom the map, click on points for photos and quick facts, or delve into detailed pages for each landmark's full story and precise location. The atlas features a variety of fortifications, from medieval strongholds to grand royal palaces, presenting itself as the most comprehensive castle map online.

France leads with the most castles at 183, followed by Italy (179) and Germany (176). The map highlights famously covered castles like the Palace of Versailles, the Forbidden City, and the Kremlin, ranked by the number of Wikipedia language editions that feature them. Castlemap is built entirely from open data, drawing facts and coordinates from Wikidata, photographs from Wikimedia Commons, and stories from Wikipedia.

To add a castle, users can improve its Wikidata entry with coordinates, a photo, and a Wikipedia article. The curated dataset of all 2,435 castles is available for download as Geo JSON or CSV. Castlemap is free to use, requiring no account for immediate exploration.