Stream access in Montana represents a conflict of rights. The state owns the bed and banks of all rivers and streams that were navigable at the time Montana entered the Union. But many hundreds of miles of waterways were not navigable and are now owned by private property owners. Those property owners hold title to the bed and banks and pay property taxes on them, and presumably have all the property rights that they enjoy for other property. But in Montana, the public also has the right to use water resources for recreation. The Montana Supreme Court has determined that it is not considered a trespass for a recreationalist to walk on the privately-owned bed and banks of naturally-occurring waterways.
The legal theory underlying Montana's stream access law was called into question in a recent U.S. Supreme Court decision in PPL v. Montana (2013). In a unanimous decision, the high court struck down the Montana Supreme Court's ruling in a case where the state of Montana had attempted to assert ownership on the streambeds upon which hydroelectric dams were built. The state's attempt to assert the "public trust doctrine"—the legal doctrine used to justify stream access—was roundly rejected by the Court.