Rath/Heumar is a quarter of Cologne, Germany. It is located in the eastern part of the city, in the borough (Stadtbezirk) of Kalk.
Its population on 31 December 2004, was approximately 11,000.
Rath/Heumar lies on the eastern edge of Cologne, bordering on its eastern side the Königsforst recreation park . To the east are the municipalities of Bergisch Gladbach and Rösrath, to the south Cologne-Eil, to the west Cologne-Gremberghoven and Cologne-Ostheim, to the north-west Cologne-Neubrück and to the north Cologne-Brück. Housing density is lower than in more central parts of the town, and many of the residential zones are dominated by detached family houses.