Photograph of Hartman Richter’s house in Germantown, MD where George Atzerodt and Hartman Richter were arrested. The house burned down in the 1980’s.
Image Source: Joan Chaconas, Surratt House Museum
Hartman Richter’s House
The History Behind Lincoln's Assassination
LincolnConspirators.com 
What was the address as there a plaque telling of it?
Steve,
I don’t recall the old street address of the Richter home at the moment, but it was located on land that now holds the Maryland Soccerplex. Here are the GPS coordinates for where the home used to be: 39.1514791, -77.3067274. There is no plaque or marker there.