North America map is around 1.8gb in size. You can get smaller sized U.S. maps based on your location in the U.S. they are around 100mb to 250mb in size.
The areas they offer are: Midwest, New England, Plains, South Central, South East, and Western Regions.
Here's more info regarding what states they cover:
http://www.tomtom.com/products/maps/...guage=1&D=1089