I'd like to see more pics. Maybe one from a bit of distance to get a scope of the entire building. Hard to tell if it's a wall from a house or a barn.
If you're in Ohio...those weathered boards probably aren't that awfully old....maybe 40 years tops if they were sealed at one time. And some of those mortar joints look fairly recently redone...like in the last 30-40 years.
Maybe an old barn structure..or chicken coop...thus the gate and fence??
Maybe something from the early/late 40's or so.
Check the nails in the wood...do they look square or machined? Was the rest of the structure removed or did it crumble?
I'd still be checkin it out if you could. Caches were burried in all kinds of places. Maybe some neat old relics layin around.
Depends on what state you're in. Building techniques differed from the east, to south, to west, etc.... In that were in CA, I'd guess mid to late 1800s. Check the nails in the wood: square nails went out of vogue in the late 1890s. So if it's got square nails, it's probably post 1900. Of course bear in mind that there could be round nails AND square nails both in a structure, if later rennovations occured.