A locator (text-free) map showing the Electorate of Cologne as of 1645.  This is based on Willem and Joan(nes) Blaeu's 1645 map File:Blaeu 1645 - Coloniensis Archiepiscopatus.jpg.  Cologne was not part of the Electorate, although it was part of the Archibishopric.
The gray lines show modern day national borders.  Except for the Emscher river, the rivers are shown in their modern routes/channels/paths.  Major cities are shown with circles, and Bonn is shown as the capital of the Archbishopric.  

Mercator projection.   A scale is at the bottom layer of the SVG (you will need an SVG editor to see it).
Own work
MapMaster