Manco brand or type wheels for sure, used by lots of mfgs . As mentioned already, Arctic Cat ONLY used 6" in this style. I don't see any threaded holes in the webbing so this was a front wheel with no brake. All but the cheapest Arctics had front and rear brakes.
Holes further out are odd. Looks like someone modified it, maybe for a sprocket.
Tire is not the right style for Arctic Cat either. They usually had trials that were more rounded in appearance with tread that came down the sides a bit. This one looks squared off. If course, it could have been replaced.
Hard to say what it came off of but it can be used on a lot of bikes depending on diameter. 6" was probably most common. Threaded holes in the webs can easily be added for sprocket mounts or Cherry/Manco drum brakes. It's a good wheel if you can deal with the holes.