There are a number of sites hosting high resolution jpegs of old London maps. MAPCO has about 12 of them dating from 1560 to the end of the nineteenth century. MAPCO’s self-proclaimed intention is “to provide genealogists, students and historians with free access to high quality scans of rare and beautiful antique maps and views.” Maps are sliced up into smaller image pieces but each image is clear and easily readable. Also included in the MAPCO collectiion is a map of England dating from 1840 (“5 miles to the inch”), a few Australian maps dating from the same time period and a map of Scotland. Worth looking at if only for the fine details.

Old London Maps has a similar but smaller collection of maps, focusing on London and dating from 1658 to 1872. These maps are also sliced up into smaller, high resolution pieces.

By way of the Victorian Dictionary, which also has a few links to a number of other Victorian-era maps.

All of this by way of atlas(t)