Old Maps Online is a great web tool for educators. It is basically an easy to use gateway to historical maps in libraries around the world. Old Maps Online has a sophisticated search engine that enables users to look for and find digital historical maps across various collections using geographical search.
If you are searching for historical maps near where you live then Old Maps Online will definitely give you a hand. By default it searches for maps about locations in your vicinity but you can customize and refine your search options to make it more specific. You can for instance search by typing a place-name or by clicking in the map window, and narrow by date. Just bear in mind that Old Maps Online does not hold the maps that you find through their search box but rather provides a direct link to the map image on the website of the host institution.
Old Maps can be a great learning tool for students. They can use it when working on history project to find relevant maps and since it is free and easy to use then there is no reason not to give it a try.