Blog · October 14, 2026 · Montana
Big Horn County Plat Book: finding and using one
If you're looking near Crow Agency, plat books show ownership by township; the parcel viewer shows it today.
Main page: Big Horn County, MT GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Hunting for the latest Big Horn County plat book? These atlases map who owns rural land, page by page, useful for farms near Lodge Grass. Covered here for Big Horn County: how the atlas is organized, where to look for printed copies, and the free online map that stays current.
The Big Horn County plat book: start here
With a lot near Bighorn Canyon National Recreation Area, plat books are commercial atlases, showing rural owners and tract lines, page by page across the county.
Where the parcel data lives
Go first to the Montana Cadastral; it maps every tax parcel in the county, Bighorn Canyon National Recreation Area included. When a rural tract has no street number, follow the nearest road on the aerial and select the outline, for land near Forty Mile Colony included. For a tract near Fort Smith, write down the parcel ID while you have it open; each records desk in the county uses it to find the file.
A homemade atlas
Print parcel views near Bighorn Canyon National Recreation Area township by township to build your own up-to-date atlas.
Who uses plat books
Farmers, hunters and appraisers near Crow Agency use plat books for a big-picture view of who owns what.
Offices that can help
If the acreage or value on a parcel near Muddy looks off are handled by the Montana Department of Revenue, which maintains the tax roll. Building or septic questions for a lot near Fort Smith are for the local planning and health departments, and the answer depends on jurisdiction.
Sections, lots and bearings
Montana follows the Public Land Survey System, which means a tract near Hardin is described by section, township and range. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though sections near Crow Agency can be irregular. Write down the legal description for the tract near Crow Agency when you talk to a surveyor.
Finding a printed edition
Not every county has a current edition, check with local offices and farm stores near Lodge Grass.
Using the parcel viewer instead
The Montana Cadastral is updated more often than any atlas, including rural land around Lodge Grass.
Not the same thing
For a tract near Bighorn Canyon National Recreation Area, don't confuse the atlas with a recorded subdivision plat: the recorded plat at the County Clerk and Recorder is a legal document, while the atlas is a reference.
Neighboring parcel maps
Big Horn County touches Carbon County, Powder River County, Rosebud County, Treasure County, and Yellowstone County, all with their own assessor records. A tract near the line by Hardin can be split across two assessors' files, so look at the adjacent map as well. For land near Fort Smith, the Platbookmapper state page lists every bordering county map for Montana.
Places you'll see on the map
Hardin is the county seat, where most land records are kept. You'll also find Lodge Grass, Busby, Crow Agency, and Fort Smith, each with its own cluster of lots. Roughly 12,751 people live in Big Horn County (Census Bureau estimate, 2023) across some 4,998 square miles. Big Horn County dates to 1913, and some chains of title near Crow Agency are long. Places such as Bighorn Canyon National Recreation Area are easy to spot when you zoom out.
Taking the map into the field
The parcel map usually runs in a mobile browser, which helps when you're standing on land near Lodge Grass, so load it before you lose signal. A saved image of the lot near Hardin and its lines is a good backup.
A word on accuracy
For acreage around Forty Mile Colony, listed acreage is an estimate; just a licensed surveyor can set the real corners on the ground. If the land is near Lodge Grass, records update in batches, so a deed recorded last month might lag behind.
Recorded documents worth pulling
When the details count, get the recorded deed through the County Clerk and Recorder; the parcel line is a drawing of it, which applies near Forty Mile Colony as much as anywhere. Inherited tracts around Bighorn Canyon National Recreation Area can sit on several deeds, and a title company can sort it out on a real sale.
Frequently asked
How accurate are plat book acreages near Muddy?
Usually, atlas drawings near Forty Mile Colony are simplified; they're good for orientation.
Should I use the Montana Cadastral instead for land near Hardin?
For a tract near Crow Agency, the Montana Cadastral is free and updated more often; many people use both.
Are old plat books online for land near Crow Agency?
Around Lodge Grass, some older atlases have been digitized.
Is a plat book legal proof in Big Horn County?
Near Lodge Grass, a plat book is a privately published atlas; use a surveyor for lines.
How do I save a parcel from the viewer around Bighorn Canyon National Recreation Area?
For a tract near Busby, most viewers have a print or export tool; downloads of raw data vary by county.
Open the official Big Horn County, MT parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.