DARIAH-DE offers the Getty Thesaurus of Geographical Names REST Service , a tool to quickly identify TGN IDs.
Getty Thesaurus of Geographic Names Online (TGN) is a thesaurus of the J. Paul Getty Trust, which represents both current and historical names in various languages hierarchically and has been developed for use in museum documentation. It contains approximately 1,106,000 records, which describe 91,200 places. Furthermore, the thesaurus contains additional information on the recorded locations such as approximate geocoordination or a categorization by location type, and also distinguishes between geophysical and geopolitical data sets. Since July 2014 the TGN is available as open metadata.
The Getty Thesaurus of Geographic Names only provides approximate information for referencing with coordinates. Most Thesauri do not go down to the level of buildings, streets or even points.
DARIAH-DE provides an eXist instance of the TGN, that is based on a dump of Getty data.
Follow this link to get to the REST API documentation of the provided service.