Constituency map of the German Empire 1871-1918.
This  map has been made or improved in the German <a href="https://de.wikipedia.org/wiki/Wikipedia:Kartenwerkstatt" class="extiw" title="de:Wikipedia:Kartenwerkstatt">Kartenwerkstatt</a> <i>(Map Lab)</i>. You can <a href="https://de.wikipedia.org/wiki/Wikipedia:Kartenwerkstatt/Kartenw%C3%BCnsche" class="extiw" title="de:Wikipedia:Kartenwerkstatt/Kartenwünsche">propose maps</a> to improve as well.
CC BY-SA 3.0
Self made, with help of <a href="//commons.wikimedia.org/wiki/File:Karte_der_Reichtagswahlen_1907.jpg" class="mw-redirect" title="File:Karte der Reichtagswahlen 1907.jpg">this map</a>