The Wisconsin Historic Society is a great resource for online research with its collections of images, books, newspaper articles, historic buildings, etc. Now they have added online browsing to a portion of their map collection which includes several amazing old maps of Milwaukee. The Increase Lapham drawing of the city from 1836 shows all of the landholders in the town. An 1856 birdseye map will keep you occupied with the amazing detail as you zoom in.

View the page for their online collection here.