Montana Fence Law: Open Range, Livestock and Partition Fences

Is Montana an open range state?

Yes, in the sense most people mean. MCA 81-4-203 defines open range as all lands in Montana not enclosed by a fence of not less than two wires in good repair, and it includes highways outside private enclosures that the public uses, whether or not they were formally dedicated. In practice that means a great deal of rural Montana is open range unless someone has fenced it or it sits inside a herd district.

Open range does not mean every animal may roam. MCA 81-4-201 makes it unlawful for an owner to willfully permit swine, sheep, llamas, alpacas, bison, ostriches, rheas, emus or goats to run at large. Cattle and horses are not on that list, which is why the classic open range problem in Montana is cattle, and why the burden traditionally falls on the landowner who wants them kept off.

What does fencing out mean?

It means the person who wants livestock kept off their land is the one who fences. The clearest statement is MCA 81-4-215: if cattle, horses or other domestic animals break into an enclosure and the enclosure's fence is legal under 81-4-101, the animal owner is liable for damages if the owner or person in control of the animals was negligent. The same section says a legal fence is not required to sue over animals running at large contrary to law, and it points herd district cases to a separate section.

Two narrower rules follow the same logic. MCA 81-4-216 lets the owner of planted trees recover for damage done by animals if the trees are inside a lawful fence or boxed to a height of not less than 5 feet. And within state grazing districts, MCA 76-16-322 says farming lands must be protected by the owner or lessee to the extent of a legal fence, and the district is not liable for damages unless that fence is in place.

What counts as a legal fence in Montana?

MCA 81-4-101 sets the standard. Apart from two exceptions, a legal fence must be at least 42 inches and not more than 48 inches high. The section then lists the types that qualify:

Barbed wire: at least three barbed, horizontal, well-stretched wires, the lowest not less than 15 or more than 18 inches from the ground, fastened to substantial posts not more than 20 feet apart, or 33 feet apart where two or more stays or pickets are used between posts. Woven wire: standard woven wire on substantial posts not more than 30 feet apart, with two barbed wires above it. Rail: four boards, rails or poles on standing or leaning posts not over 17 feet 6 inches apart, with a brace on the inside of each leaning post. Other barbed wire fences that are as strong and as well calculated to protect enclosures as the listed types.

Electric fences qualify too, if they have at least three tightly stretched strands of at least 12.5 gauge high-tensile steel or equivalent, posts averaging not more than 50 feet apart, a charger with an output of at least 0.5 joule, and regular maintenance by the owner. Any of the other legal fences with an added electrified strand still counts. Rivers, hedges, ridges, bluffs and other barriers stock cannot pass are legal fences as well, and the statute has a separate taller standard for corral fences around stacks.

Can a fence that is not a legal fence create liability?

It can. MCA 81-4-103 says anyone constructing or maintaining a fence of any kind not described in 81-4-101 is liable in a civil action for damages caused by injury to stock resulting from the defective fence. Barbed wire has its own duty: under MCA 81-4-104, a person who receives written notice that their barbed wire fence is down or likely to injure livestock and does not repair it is liable for the value of animals injured by it.

Neglected wire is also a public problem. MCA 81-4-105 declares barbed wire and other wire fencing that has sagged or fallen to the ground, so that it no longer turns stock and is a menace to people riding or walking over it, a public nuisance subject to abatement. If you have bought land with old wire lying in the grass, removing it is more than tidying up. Our guide to wildlife-friendly fencing covers how old wire affects deer, elk and antelope as well.

What is a herd district?

A herd district is an area where the usual open range rule is reversed for the months it is in effect. Under MCA 81-4-301, a herd district is created by petition to the county commissioners, either from owners of 55 percent of the land when at least 25 percent is cultivated or residential, or from owners of 75 percent of the land. The petition names the months the district is in effect, and the commissioners hold a noticed hearing before creating it. Most districts must be at least 12 square miles.

Inside a district, letting livestock run at large is a misdemeanor under MCA 81-4-306, and MCA 81-4-307 makes the owner of a trespassing animal liable for care, feeding and damages, with a procedure for the landowner to hold the animal and give written notice. MCA 81-4-311 says that when a district is created, fences must be built by the entities creating it, maintained under 70-16-205, and conform to 81-4-101. Whether your parcel is in a herd district is a question for the county commissioners or clerk and recorder in Missoula or Ravalli County, not something to assume from the neighborhood.

Who pays for the fence between two neighbors?

Montana's answer starts with MCA 70-16-205: adjoining owners are mutually bound equally to maintain the boundaries, monuments and fences between them, unless one owner lets their land lie unfenced. If that owner later encloses the land, they must refund a just proportion of the value of the division fence the other owner built. The statute adds that grazing or pasture use counts as using the land, so pasture is not idle ground.

The same section sets a default split. Except as provided by prescription, custom or agreement, each owner maintains the fencing to the right of the midpoint of the common boundary as viewed from their own land. There is a rule for land entirely surrounded by another owner's, and where terrain differs substantially, responsibility is to be worked out by mutual agreement considering cost and time. MCA 70-16-206 adds that where both neighbors enclose their land, they build and maintain the partition fence in equal shares and keep it in good repair year round unless they agree otherwise.

What notice do you have to give a neighbor about a partition fence?

The notice periods are specific. Under MCA 70-16-207, a neighbor who encloses land next to your existing enclosure must, within 3 months, build their share of the partition fence or refund an equal proportion of its value. Under MCA 70-16-208, where land was enclosed in common and one owner wants to occupy their part separately, the other must build their share within 6 months after written notice, or the first owner may build it and recover the cost.

For repairs, MCA 70-16-209 lets the adjoining occupant build or repair a neglected partition fence at the other party's expense after giving 60 days' notice that a new fence should be erected, or 5 days' written notice that repair is necessary. And MCA 70-16-210 says an owner who wants to let land lie open must give at least 6 months' notice before removing their share of a partition fence, unless the neighbor pays or tenders its value. Written notice that you keep a copy of is the sensible habit with all of these.

Does fence law apply to a house lot in town?

Mostly no. The livestock sections matter where livestock are present, and a city lot is governed day to day by city fence rules: permits, heights and setbacks. In Missoula, for example, the city fence code prohibits barbed wire in residential areas. We cover the local rules in fence height and permit rules in Missoula and the Bitterroot. The partition fence sections in Title 70 are written for adjoining owners generally, but on small lots most neighbors simply agree in writing who builds and who maintains.

Rural subdivisions sit in between. A five-acre lot next to pasture may be on open range, so a neighbor's cattle in your yard may be your fence problem rather than theirs. Check whether you are in a herd district, read any covenants, and build to the 81-4-101 standard on the side facing livestock if you want the protection the trespass statute gives a legal fence.

How does the law affect the fence you build?

Three practical points. First, if you are fencing against cattle or horses on open range, build a fence that clearly meets one of the 81-4-101 types: right height band, right wire count and bottom wire height, right post spacing. A good-looking fence that does not meet the standard may not give you the protection you expect. Our guides to horse fencing and split rail and buck-and-rail fences cover the common options.

Second, build on your own side of the line. A partition fence agreement is one thing, a fence that wanders onto a neighbor's land is another; see fences and property lines. Third, call 811 before anyone digs. Under MCA 69-4-503 the excavator must notify the notification center before excavating, and facility owners generally have 2 business days to locate and mark.

Where HJ fits

We build and repair fences across Missoula and Ravalli counties: cedar and treated wood, privacy, chain link, vinyl, post and rail with welded wire, and ranch fencing. We are not attorneys and do not give legal advice, but we will build to the standard you need and set posts deep enough to stay there; see our custom fencing and fence repair pages. This guide is part of our Montana Landscaping, Lawn & Irrigation Guide.

Call HJ Property Care & Tree Service at (406) 215-7319 or request a free fence estimate and we will walk the line with you.

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