First, you can only hunt in MN’s territorial waters under your resident license. That means, for most parts of the river, it is mid channel and west. Some islands are in WI and some are in MN. For you to hunt an island, you would need to know what state it is in.
If you wanted to hunt both sides of the river, you would need to possess all licenses needed for both states. The Federal Duck Stamp is the only one that works for both states. So you would need a resident small game, MN state duck stamp and HIP certification from MN. Then, a non-resident small game, WI state duck stamp (if there is one) and HIP certification for WI and one Federal duck stamp for both states.
Second issue is to duck hunt from water, you need to partially conceal you and your boat with natural vegetation. This is sometimes hard to find on the main part of the river and is best in back waters. Most of St. Croix is too large to float down and shoot. You are allowed to do this on rivers under 100 yards wide.
Third issue is with the government shutdown, technically all National Park Service boat launches are closed. I am not sure if they are enforcing this or not. The NPS park rangers are on duty still but only as essential employees.
Last issues is hunting from land. You can hunt from land on the St. Croix river since most of it is NPS land. All state parks would be off limits to hunting from land. The issue again comes up that the National Park is closed, so technically you are not allowed to hunt from NPS land either.
Pigeonator- this is what the DNR sent me about hunting the river