cartomundi offers about 35 000 references of cartographic documents. they cover 185 countries and are hold in about 20 different map libraries.
the british library has a georeferencing project which features over 3,000 more maps from the british library collections.
the library of congress has custody of the largest and most comprehensive cartographic collection in the world. the online map collections represents only a small fraction that have been converted to digital form.
check out the history of cartography project.
you can also read the print copy from the reference collection on the main floor of the library: call number ga 201 h53 1987