The Michigan Supreme Court settled a dispute like this back in 2005, after a neighbor had sued another neighbor for walking along their beachfront property.
The court ruled that the right to walk along beachfront property extends up to the ordinary high water mark in Michigan. The high water mark was defined, in-part, this way by the Michigan Supreme Court:
"The point on the bank or shore up to which the presence and action of the water is so continuous as to leave a distinct mark either by erosion, destruction or terrestrial vegetation, or other easily recognized characteristic."
Now, the Ohio Supreme Court has chimed in. From the Associated Press:
The Ohio Supreme Court has ruled that beachcombers can legally walk from the water to the "natural shoreline" along properties bordering Lake Erie.
The Wednesday ruling comes in a case pitting thousands of lakefront property owners against the Ohio Department of Natural Resources, which establishes public access rules.
In a 7-0 decision, the court reversed an appellate ruling that said property owners' rights extend to the point the shore and water meet on any given day.
The high court also rejected state arguments that public access should extend to a high water mark established in 1985.
Justices define the natural shoreline as "the line at which the water usually stands when free from disturbing causes."
It says its ruling reaffirms decisions dating to 1878 and state law enacted in 1917.