you are correct about the state lines - i live near the potomac in great 
falls, va - hunters are allowed to shoot geese and ducks from the va side if they 
have their feet in the water- shooting off firearms in fairfax county, where 
this is, is illegal - but if it is a hunting season in maryland, they can do it 
if in the water   - this weekend we saw about 200 ring necked ducks in the 
potomac just above riverbend park , both sat and sunday afternoons in the same 
place - about halfway up the river from riverbend to seneca road on the va side 
- christie huffman