We have owned a house for over 20 years in a town established in the early 1900's. There are alleys behind the two streets in town. We are one lot from the end. The corner lot owner regularly parks vehicles in the alley (not part of any lot) but he moved them in the past when we said we needed access (while we were living there). Two months ago he dumped a big pile of brush blocking vehicular access to our garage/backyard. We are currently renting the house out and the tenants don't care about access to the alley but we needed to remove an appliance and when we went to gain access to the back and couldn't I asked him to move the pile of brush. He said he wasn't going to and he was going to annex that part of the alley into his lot because he's maintained it for 21 years. Can he do that?We live in Maryland. I think the county owns the land but am not sure. It shows up on the same plot record of ownership as the streets. The residents all mow the alley behind their houses. He put down gravel behind his part. We are the main ones that accessed the alley with a vehicle and regularly used it with our vehicles in 2009-2010. He would reluctantly move his equipment and vehicles when he blocked access during that time. This is the first time he has refused to move his stuff and declared his intent to 'annex'. Argh! Any advice?