A linguistic map is a thematic map showing the geographic distribution of the speakers of a language, or isoglosses of a dialect continuum of the same language. A collection of such maps is a linguistic atlas.
The earliest such atlas was the Sprachatlas des Deutschen Reiches of Georg Wenker and Ferdinand Wrede, published beginning in 1888, followed by the Atlas Linguistique de la France, of Jules Gilliéron between 1902 and 1910, and the AIS - Sprach- und Sachatlas Italiens und der Südschweiz of Karl Jaberg and Jakob Jud, published 1928–1940. The first linguistic atlas of the US was published by Hans Kurath.
General:
German:
French:
Italian: