Deer hunting in Montana can be for either Whitetail or Muleys. While there are some areas where you might find both species together normally you are looking for different terrain to hunt whitetails from muleys.
Whitetails in Montana are viewed as more of a nuisance by most Montana residents. Farmers and ranchers definitely view them as a nuisance most times. These will be bigger body deer that grow thick antlers but a score in the 160s is high for Montana whitetails. Due to usually being located in riparian land along creeks, streams and rivers adjacent to cropland you will have the opportunity to see numerous deer feeding in the fields. It is not uncommon to see a hundred deer in a field at dusk or dawn.
Whitetails are going to stick close to that riparian land due to the cover, water and cropland forage. This means up and personal close range shots whether archery or rifle. Whitetails are likely going to be a general over the counter type license that is readily available for residents and non residents. Deer hunting in Montana for whitetails offers ample opportunities for both private and public land. If you are willing to knock on enough doors you have a decent chance of hunting private land. You just have to find the right farmer or rancher that is tired of feeding the nuisance whitetails.
Mule deer have a niche following in deer hunting in Montana. While numbers are down from several years back the muley is starting to make a good recovery in many parts of the state. You can find muleys in high altitude forests and meadows or you can find them in the sagebrush coulees of Eastern Montana. The really good bucks are going to be in the hard to get to spots unless it is rut. That is when they let their guards down and can be caught in easier to hunt spots. Sometimes mixed in with elk but normally they are in rough country and not mixed with elk or whitetail.
Muleys are noted for their distinctive hop. Good bucks will go 180-200 score and antlers will be wide. There are not as many mule deer hunters as whitetail hunters in the world. Most of that is due to location and the number of whitetails vs muleys. Part of that is the mule deer has somewhat of a bad rap for not tasting that good. Not always true. Another reason is you normally have to be a much hardier hunter to hunt muleys in higher altitude or much more walking and stalking.
Deer hunting in Montana has a lot to offer with both mule deer and whitetail. It is a great place to archery hunt. If you are mule deer hunting in high country I would suggest carrying bear spray. Very unlikely to ever use it but it is your best bet for that one in a million chance of a bear charge.
If you want to read about more big game hunting in Montana read about Alpine hunting in Montana.