The German advance reached the proverbial gates of Moscow in the late fall of 1941, which is essentially the high-water mark of their efforts on the Eastern Front. The bulk of German forces were out of sight of the city, but on Nov. 30th, scouts from the 62nd Panzer Pioneer Battalion were able to get within view of the city, only a couple mile from the edge of the city, the furthest any German soldiers would make it. They would begin to be pushed back with the Soviet counter-offensive launched on Dec. 5th, and never get quite so close again.

I would note that in 1942, the German advanced into the Caucuses as part of Case Blue in an attempt to take the Caucasus oil fields, and penetrated quite deep, nearly to Grozny. With the catastrophe at Stalingrad though they were quite vulnerable so were forced to begin a withdrawal before the end of the year.