In a truly disturbing article, the New York Times detailed recent research by the United States Holocaust Memorial Museum to identify all the camps established by Germany in World War II, be them extermination camps, labour camps, ghettos, &c. At one point in the article, one of the principals behind the USHMM work stated he expected to find as many as 7,000 such camps across Europe. They have currently identified 42,500.
Two maps accompany the article. The first details the reach of ghettos for Eastern European Jews.

This second map plots the locations of the primary and secondary SS concentration camps.

Credit for the pieces go to the New York Times.