Most people who ask this question have one of three things in hand: an old deed from a parent or grandparent, a letter from a landman or a mineral buyer, or a royalty check that arrived out of nowhere. Whichever it is, the path in Montana is the same four steps.
Montana is surveyed from the Montana Principal Meridian: section, township north, range east or west of that line — watch the east/west, it is the classic transcription error on a Montana deed. The description is on the deed, on any division order you signed, and usually printed in the property column of a check stub. Write down every tract, including any government lots (irregular parcels along rivers and section edges, described as "Lot 3" rather than a quarter-quarter).
Mineral deeds, reservations and leases are recorded with the Clerk and Recorder of the county the land sits in — not with the state. Montana's 56 county clerks and recorders keep the grantor/grantee index; the oil counties (Richland, Roosevelt, Fallon, Toole, Glacier) will run a search by mail or over the counter, and several have gone online. You are looking for the instrument that gave your family the minerals (a mineral deed, or a warranty deed that reserved the minerals when the surface was sold) and for anything that later conveyed them away. If the trail runs through a death, look for a probate, a decree of distribution or an affidavit of heirship in the same index; minerals that were never formally passed on are the most common reason a check stops or never starts.
Federal minerals are a large share of the Montana estate, particularly in the north and east (BLM Montana-Dakotas, Billings), and the Fort Peck and Blackfeet reservations carry tribal and allotted minerals administered by the BIA. State trust minerals belong to the Department of Natural Resources and Conservation. A 1910s homestead patent that reserved the minerals to the United States is the most common reason a Montana surface owner turns out not to own what is underneath. The map shades federal minerals so you can see at a glance whether the section you own surface on has private minerals at all.
Once you have a tract, look at it. Montana Board of Oil and Gas Conservation records will tell you which wells have been permitted, drilled and produced on that section and, through spacing orders, which horizontal wells a mile away are draining it. If there is production and you are not being paid, the operator's division-order department is the next call; if there is a rig on the way, a landman will find you before long. Montana's activity is concentrated in the Williston Basin (Richland, Roosevelt, Sheridan — Elm Coulee is the state's biggest field), the Cut Bank and Kevin-Sunburst fields north of Shelby, the Bowdoin gas field in Phillips and Valley counties, and the Montana side of the Powder River Basin; if your tract is there, assume someone else already knows about it.
Put the tracts, the recorded instruments and the fractions in one place. Owners who can answer "what do I own and where" in one sentence get paid faster, negotiate better leases and hand their heirs something other than a shoebox. If you own in more than one state — common for families who homesteaded across the Rockies — keep one set of books per person or trust and tag each tract with its state.
No. Ownership is proven by documents recorded with each clerk and recorder. MBOGC records show wells and production, not who owns the minerals under them. Federal mineral ownership is a BLM record; tribal minerals are a BIA record.
Probably. Operators pay the owner of record, often found through a title search after a well is drilled. Ask the payor for the division order and the legal description it is based on, then confirm the chain of title at the county.
It depends on whether they are producing, what the wells are making, how much undrilled acreage sits inside an active spacing unit, and current prices. Look at the section's production history and nearby spuds before you answer a buyer's letter.