Where to Look for Historical Maps ? GIS Lounge, 28.01.2012 (source JS)
Old Maps Online, has made finding those maps a whole lot easier.
This Porsmouth portal that allows to search geographically via some of the largest online map collections :
the David Ramsey Collection,
the British Library,
the Moravian Library,
and the National Library of Scotland.
L'article cite également :
The Library of Congress (LOC) Map Collections
The British Library (OS, Crace Collection)
Big Map Blog