I believe that the only state laws in MN are that you need permits to keep Timber Rattlers and Massasaugas but that has more to do with the fact that they're species of special concern (endangered) rather then venomous. However each city/town will have their own municipal ordinance which will vary between no mention at all to a complete ban. If would be impossible to give you a listing of ordinances town by town, you'd have to check with the city hall of each one you were interested in moving to. However many of them will have that info listed online these days.