Civil War era Medium Size US belt plate worn by Union soldiers.  This is an unusual size and quite scarce. 
It is from the noted buckle collection of George Kegerreis.  I bought it personally at the auction sale of his collection some years ago in Pennsylvania and it has been a part of my retained collection.  It is a very fine specimen and I will be happy to write and supply a letter of its provenance with it. I would consider it an honor to pass along that connection.