In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Agar Town like this:
AGAR-TOWN, a metropolitan suburb in St. Pancras parish, Middlesex; 2½ miles NW of St. Paul's. A chapelry is here; and the living is a vicarage See London.
This is approximately the location shown in a detail from a map in Cross's London Guide (1851), reproduced in the Wikipedia article on Agar Town. Additional information about this locality is available for St Pancras
A Vision of Britain through Time includes a large library of local statistics for administrative units. For the best overall sense of how the area containing Agar Town has changed, please see our redistricted information for the modern district of Camden. More detailed statistical data are available under Units and statistics, which includes both administrative units covering Agar Town and units named after it.
GB Historical GIS / University of Portsmouth, History of Agar Town, in Camden and Middlesex | Map and description, A Vision of Britain through Time.
Date accessed: 30th March 2015
Click here for more detailed advice on finding places within A Vision of Britain through Time, and maybe some references to other places called "Agar Town".