Kartenmeister.com for Prussian genealogy is an indispensable tool. It’s difficult not to jump up and down as I write this because this resource is so great.
The brainchild of Uwe-Karsten Krickhahn, Kartenmesiter.com contains 94,636 locations in the former country of Prussia, with 38,691 locations that have changed to Polish, Lithuanian, or Russian names.
You can search by:
1. German name
2. Older German name
4. By the next larger town (proximity search)
5. Current Polish, Russian or Lithuanian name
6. By Family Name
As seen in the example at right, search results include the all important Kreis, GPS, and other information to further your research.
Best of all is the option to attach the surnames you’re researching in a particular town and view surnames other researchers have posted as well.