Found the lock now I need to find the lock box!!

[peanut]

Went to an old house place on the neighbors today and found a few things, only two of them were worth posting. My neighbor told me the house was where his grand parents lived and he is in his 70's. He told me he thought the house was built around 1870 something. Any ideas as to what that big of a lock would've went to? It has D M & CO. stamped on it.
Thanks for looking, peanut
p.s. Yes I know it is not feb. 7, the date on the camera is wrong.

 

[allen]

wtg on those neat relics !

 

[spartacus53]

nnice looking relics