Part of the problem is you lack being able to answer pertinent questions. Until you do some real research and get some real answers anything offered is nothing more than speculative.
Let me toss out a few things to try to help.
If the waterway is navigable the public has a right to travel upon it.
The owners of any land have a right to control their land and deny trespass.
unless there is some right of way or easement to access the bridge the owner of the land it rests upon has effectively control of the bridge even if they are not the actual owners of the bridge BUT based on laws regarding fixtures and chattel unless it is a mobile bridge or some other contractual relationship affecting the matter, ownership of the bridge belongs to the owner of the land which it sets upon.
The only issue at that point is whether the owner of the land underlying the waterway can enforce a right to prevent trespass on (over) their land. The law used to consider the land to the center of the earth to the heights of heaven above as belonging to the owner of the land. That has been trimmed a bit to limit the airspace to that which a person can reasonably use. Given the bridge is likely to be a matter of feet above the land, technically the owner of the land under the waterway could in fact enforce a right of control on traffic on the bridge (although the right of travel upon a navigable waterway slaps the rights to airspace above one's land in the face and might afford an argument to deny the troll the right to control travel upon the bridge. That is a question that would require research.)
What is likely to be quite important to the issue is the history of the bridge and involved lands. Knowledge in that area may provide a relatively simple answer to most all questions of the matter. That is where your lack of knowledge prevents any substantive answers to be offered.
Thanks, that makes perfect sense. To complicate matters even more, I have a State Transportation Department map circa 1930's that shows "County Bridge" as well as actual photos of the bridge from the same time period. Of course, the county has denied ownership. A similar situation occurred with a neighboring subdivision. After years of expensive litigation, the judge declared the county owned that bridge but the PA ignored the judge (hard to believe, I know.) So, the State stepped in and, using federal highway dollars, repaired that bridge.
The odds of this happening again are slim to none and folks in my subdivision cannot afford to hire an attorney and sue the county.
In the meantime, this new association has stated they own the bridge and think they can force us to join and want a copy of our Warranty Deed. That is not going to happen
We are hoping we can simply pay our fair share of bridge repair monies and call it good. We shall see. Thank you again, it is refreshing to find someone who actually understands this mess.
Happy Easter!