There are so many hikes in Montana that are enjoyable on public land. That doesn’t stop the debate over public access through private land. It is a hotly debated topic whether public access should be guaranteed through private land. If you want a guide for public hikes in Montana and that would be 99% of the hikes here is a great Montana hiking guide website. It has interactive maps that show areas all over the state. Some private landowners give access to public lands through their property. In all fairness, it is about the law and if you know private landowners that have given rights through their land many are left to clean up, maintain roads and deal with issues. I know one gentleman that spent time, money and effort each year keeping the trail and road up through his property and would have to pull stuck atvs out and pick up trash and repair gates and fences.
If you want to try and access private hikes it is all about how you go about it and who you know. First thing you can try is politely knocking on ranch doors and just asking. This is the way hunters use to ask and some still do with success. This is a numbers game and you will find someone that says yes it is just about how many doors you have to knock on. Count on 1 out of 10 saying yes which means 9 out of 10 say no! The beauty is once you find the one that says yes if you send them a gift thanking them they will usually say yes again. This isn’t the big city and people are polite in Montana especially ranchers.
Another idea is to ask at the local diner after you have been a couple of times and gotten to know the waiter/waitress. They know everyone and usually there will be ranchers in the diner so many times you will get an introduction right then. Another way is to get to know a real estate agent that specializes in Montana land for sale. Many times you can get an introduction especially if you are talking about purchasing some land yourself!
If you are good with public hikes keep a couple of things in mind to fight the crowds. Go to a location that isn’t close to the bigger cities or national parks. Start early and stay late. Most people don’t get up early and want to be back to where they are staying before dark. Bonus to this is you also see more wildlife. Just carry bear spray. Incredibly small chance you will ever need it but it is nice to have in case of the one in a thousand chance you need it.
Lots of hiking options in Montana and I would go the public route first but after you have hiked a long time it is nice to have a mountain or trial all to yourself. That is where the private hike and contacts are. Enjoy your day!