 <p>They buy their data from other companies to form the maps. I beleive they purchased the majority of it from Tele Atlas. <a href="http://code.google.com/apis/maps/signup.html" rel="nofollow noreferrer">http://code.google.com/apis/maps/signup.html</a></p> <p>Here is a lot of information on the history of it: <a href="http://en.wikipedia.org/wiki/Google_Maps#Map_projection" rel="nofollow noreferrer">http://en.wikipedia.org/wiki/Google_Maps#Map_projection</a></p>