The Madison isn't one fishery — it's a chain of very different reaches running from the Yellowstone Park headwaters, through the Hebgen-to-Quake lakes country, down the famous 50-mile riffle of the Upper Madison, across the walk-wade channels above Ennis, through Bear Trap Canyon below Ennis Dam, and out onto the Lower Madison toward the Missouri. Almost all of it is public water fished on a Montana license, and Montana's stream-access law keeps you legal below the high-water mark even where the bank is privately owned — but that doesn't mean you can cross private land to reach it. Above Ennis especially, a lot of the frontage is ranchland, so plan to get in through FWP fishing access sites, not by walking across someone's field. Rules change reach by reach: the Park has its own season and species handling, and one stretch above Ennis is walk-wade only with fishing from a boat flat-out prohibited. And this is heat-sensitive country. In a low, warm summer the Madison goes under hoot-owl restrictions (no fishing 2pm to midnight) or full closures, especially the Lower Madison and the Park water — always check the current Montana FWP restrictions and Yellowstone regulations before you fish.