Blog · October 14, 2026 · Montana
The Carter County Plat Book and the online parcel map
Out toward Ridge, plat books show ownership by township; the parcel viewer shows it today.
Main page: Carter County, MT GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Looking for a Carter County plat book? These atlases map who owns rural land, page by page, useful for farms near Custer National Forest. In this Carter County guide: what's in a plat book, where to look for printed copies, and the free online map that stays current.
Getting started with the Carter County plat book
In and around Mill Iron, a plat book is a privately published atlas, with owner names on each tract, page by page across the county.
Getting to the right map
For land near Medicine Rocks State Park, the public parcel map for this area is the Montana Cadastral, and it opens in a browser with no account. If you only know roughly where the land is, pan along the nearest road until the lines appear, then click inside the one you want, whether the land is near Ridge or elsewhere in the county. If you're looking near Ekalaka, write down the parcel ID before closing the panel; every records desk in the county uses it to find the file.
Finding a printed edition
Older editions near Ekalaka turn up in libraries and historical societies, useful for family or title research.
Before you lean on the lines
For a parcel near Custer National Forest, listed acreage is a tax-roll number; only a licensed surveyor can set the real boundary on the ground. On ground around Alzada, owner names and values update on a schedule, so a deed recorded last month might lag behind.
Where the recorded documents are
Out toward Ridge, the map is an index, not the title: recorded deeds, subdivision plats and easements for parcels in the county are filed with the County Clerk and Recorder. With a lot near Ridge, older tracts in the county can trace back through several deeds, so a title company earns its fee before a purchase.
Who handles what
If the acreage or value on a parcel near Medicine Rocks State Park looks off belong with the Montana Department of Revenue, since that office keeps the assessment data. Building or septic questions for a lot near Ekalaka go to planning, building or health offices, and the answer depends on jurisdiction.
Using it on a phone
The parcel map usually runs in a mobile browser, which helps when you're standing on land near Boyes, though signal can drop in rural spots. A screenshot of the parcel near Alzada with its ID helps when you meet an owner or agent.
Sections, lots and bearings
Montana uses the Public Land Survey System, so rural legal descriptions near Ekalaka cite section, township and range. A standard section is about one square mile, roughly 640 acres, and a township holds 36 of them, though real sections near Medicine Rocks State Park vary in size. Keep the legal description for land near Boyes for any title or survey request.
Between editions
Around Custer National Forest, the Montana Cadastral is updated more often than any atlas, across the county.
Next door to Carter County
The county touches Custer County, Fallon County, Powder River County, Butte County, SD, and Harding County, SD; every one of them runs a separate parcel map, especially near Boyes. Ground near Ridge that runs to the line may show up across two assessors' files, so look at the adjacent map before you assume the acreage. Closer to Mill Iron, our state page lists every bordering county map across Montana.
Carter County in a few facts
Ekalaka serves as the county seat, where most land records are kept. You'll also find Alzada, Boyes, Hammond, and Mill Iron. Around 1,418 people live in this county (Census estimate, 2023) on some 3,340 square miles for land near Ridge. The county was organized in 1917, and some chains of title near Ekalaka are long. Features like Medicine Rocks State Park help you orient on the aerial.
Atlas or legal document
For acreage around Hammond, a plat book is not a recorded plat: the recorded plat at the County Clerk and Recorder is a legal document, while the atlas is a reference.
Why people still buy them
Buyers and seed dealers around Alzada rely on them to see ownership across many tracts at once.
Making your own township pages
Print parcel views near Mill Iron township by township to build your own up-to-date atlas.
Frequently asked
Is there a current Carter County plat book?
Generally, editions come and go.
Is a plat book legal proof around Hammond?
If you're looking near Ridge, a survey sets boundaries, not an atlas; use a surveyor for lines.
Should I use the Montana Cadastral instead in Carter County?
For a tract near Alzada, the Montana Cadastral is free and updated more often.
How accurate are plat book acreages in Carter County?
If you're looking near Ridge, the deed and a survey decide.
Is the parcel map a survey for land near Ridge?
If you're looking near Mill Iron, parcel lines are tax drawings, not surveys; a survey sets the real corners
Open the official Carter 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.