When was Meagher County founded?

Meagher County was founded in 1866, formed from Gallatin County, and named after Thomas Francis Meagher.

What is the county seat of Meagher County?

The county seat of Meagher County is White Sulphur Springs.

Is there an online parcel map for Meagher County?

Yes. A public source publishes a parcel map of 6,133 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Meagher County's boundary or name changed?

Meagher County was created in 1866 from Gallatin County. Since then the Atlas of Historical County Boundaries records 18 later changes, chiefly involving Cascade County, Gallatin County and Dawson County.

Is my lot in a flood zone?

We do not have flood maps for Meagher County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

County · code 30059

Meagher CountyMontana

Meagher County is a county in Montana with its seat in White Sulphur Springs, formed in 1866 from Gallatin County. The county is named after Thomas Francis Meagher.

Founded1866
County seatWhite Sulphur Springs
Named forThomas Francis Meagher
Land area2,392 sq mi + 2.9 sq mi water
Population1,927 2020 Census
Parcels mapped6,133 checked 15 October 2026

Open the free map Click any parcel in Meagher County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated 20 October 2026

Census outline · seat marked

History

Formed in 1866 from Gallatin County

An old deed may name a county that no longer exists, or a boundary that has since moved.

Meagher County was created from Gallatin on March 26, 1866, but lost all its territory to Gallatin when Congress voided territorial acts in March 1867. Meagher was re-created on November 16, 1867, from Chouteau and Gallatin counties and went through multiple boundary changes over the following decades. The county became part of the state of Montana in 1889 and has continued to experience adjustments, including losses to the creation of Fergus, Cascade, Sweet Grass, Broadwater, and Yellowstone counties.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

1866
Meagher County created Meagher created by Montana Territory from Gallatin. Acts of the 2d and 3d legislatures were declared null and void by the United States Congress, 2 March 1867.
from Gallatin
26 March 1866 · Mont. Terr. Laws 1866, 2d leg., ch. 10/pp. 11-12; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219-228; Sanders, Helen F., 1:331-341
1867
Lost territory Meagher lost all territory to Gallatin; Meagher eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory.
to Gallatin
2 March 1867 · U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219-228; Sanders, Helen F., 1:331-341
1867
Meagher County created Meagher re-created from Choteau (now Chouteau) and Gallatin.
from Choteau from Chouteaufrom Gallatin
16 November 1867 · Mont. Terr. Laws 1867, 4th leg., pp. 99-100
1874
Gained territory Meagher gained from Gallatin.
from Gallatin
13 February 1874 · Mont. Terr. Laws 1874, 8th leg., pp. 66-67
1889
Became part of Montana Meagher became a county in the state of Montana. 8 November 1889 · U.S. Stat., vol. 26, pp. 1551-1552 and vol. 25, ch. 180 [1889]/pp. 676-684; Swindler, 6:82-83

Show all 22 changes (17 more)

1866
Meagher County created Meagher created by Montana Territory from Gallatin. Acts of the 2d and 3d legislatures were declared null and void by the United States Congress, 2 March 1867.
from Gallatin
26 March 1866 · Mont. Terr. Laws 1866, 2d leg., ch. 10/pp. 11-12; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219-228; Sanders, Helen F., 1:331-341
1867
Lost territory Meagher lost all territory to Gallatin; Meagher eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory.
to Gallatin
2 March 1867 · U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219-228; Sanders, Helen F., 1:331-341
1867
Meagher County created Meagher re-created from Choteau (now Chouteau) and Gallatin.
from Choteau from Chouteaufrom Gallatin
16 November 1867 · Mont. Terr. Laws 1867, 4th leg., pp. 99-100
1872
Changed Dawson attached to Meagher "for judicial purposes."
Dawson
4 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585
1872
Boundary clarified Meagher boundaries redefined (no change).
no change
12 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 7/p. 431
1874
Gained territory Meagher gained from Gallatin.
from Gallatin
13 February 1874 · Mont. Terr. Laws 1874, 8th leg., pp. 66-67
1876
Gained territory Meagher gained from Big Horn (original, now Custer) and Dawson.
from Big Horn from Custer from Dawson
9 February 1876 · Mont. Terr. Laws 1876, 9th leg., p. 48
1881
Changed Dawson detached from Meagher, attached to Custer "for judicial and other purposes."
Dawson Custer
19 February 1881 · Mont. Terr. Laws 1881, 12th leg., p. 122
1883
Boundary clarified Meagher boundaries redefined (no change).
no change
7 February 1883 · Mont. Terr. Laws 1883, 13th leg., p. 33
1886
Lost territory Meagher lost to creation of Fergus. Act passed 12 March 1885; took effect 1 December 1886.
to Fergus
1 December 1886 · Mont. Terr. Laws 1885, 14th leg., pp. 78-83
1887
Boundary clarified Meagher boundaries redefined (no change).
no change
1 March 1887 · Mont. Terr. Laws 1887, 15th leg., secs. 736, 743/pp. 836, 840
1887
Lost territory Meagher lost to creation of Cascade and exchanged with Fergus. Act passed 12 September 1887; took effect 19 December 1887.
to Cascade to Fergus
19 December 1887 · Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105-109
1889
Became part of Montana Meagher became a county in the state of Montana. 8 November 1889 · U.S. Stat., vol. 26, pp. 1551-1552 and vol. 25, ch. 180 [1889]/pp. 676-684; Swindler, 6:82-83
1895
Lost territory Meagher lost to creation of Sweet Grass and lost to Yellowstone.
to Sweet Grass to Yellowstone
5 March 1895 · Mont. Laws 1895, 4th leg., pp. 54-58
1897
Lost territory Meagher lost to creation of Broadwater. Act passed 9 February 1897; took effect 1 March 1897. Meagher lost to Cascade and exchanged small areas with Cascade along Smith River.
to Broadwater to Cascade
1 March 1897 · Mont. Laws 1897, 5th leg., pp. 45-52
1897
Lost territory Meagher lost to Lewis and Clark.
to Lewis and Clark
5 March 1897 · Mont. Laws 1897, 5th leg., pp. 53-55
1899
Lost territory Meagher lost to Cascade.
to Cascade
28 February 1899 · Mont. Laws 1899, 6th leg., pp. 41-42
1899
Lost territory Meagher lost to Cascade.
to Cascade
6 March 1899 · Mont. Laws 1899, 6th leg., p. 43
1911
Lost territory Meagher lost to creation of Musselshell, gained from Fergus, and lost to Broadwater. Act passed 11 February 1911; took effect 1 March 1911.
to Musselshell to Fergus to Broadwater
1 March 1911 · Mont. Laws 1911, 12th leg., ch. 25/pp. 29-38
1913
Lost territory Meagher lost small area to Gallatin when boundary was adjusted to run on federal land survey lines.
to Gallatin
8 March 1913 · Mont. Laws 1913, 13th leg., ch. 60/pp. 113-116
1917
Lost territory Meagher lost to creation of Wheatland. Act passed 22 February 1917; took effect 1 April 1917.
to Wheatland
1 April 1917 · Mont. Laws 1917, 15th leg., ch. 55/pp. 63-70
1921
Exchanged territory Meagher exchanged with Park when boundary was adjusted to run on federal land survey lines.
with Park
1 June 1921 · Mont. Rev. Code 1921, sec. 4333/pp. 1592-1593

Land and parcels

What the maps cover in Meagher

Who publishes each layer, how good it is, and when we last checked.

Parcels Good enough

Lot lines and tax-map numbers for 6,133 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 14 October 2026 · checked 15 October 2026
Address points Official

One point per address, 2,120 in all from Montana State Library.
edited 13 October 2026 · checked 14 October 2026
Buildings Reference

Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026

Official: from the office that keeps the record
Good enough: a reliable statewide or national copy
Fallback: a guide only; check the official record
Missing: nothing public found yet

People and land

Meagher by the Census

Population

1,927 2020 Census count

Housing units

1,352 2020 Census count

Land area

2,392 square miles

Water area

2.9 square miles

People per sq mi

<1 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Meagher County's official site

We have found the county's site but not its offices yet; start there.

County government

County government
The official website of Meagher County.
meaghercounty.org

See your own lot on these maps

Open Meagher County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.

Open the free map no sign-in Pro early access

Questions

Common questions about Meagher County

When was Meagher County founded?: Meagher County was founded in 1866, formed from Gallatin County, and named after Thomas Francis Meagher.
What is the county seat of Meagher County?: The county seat of Meagher County is White Sulphur Springs.
Is there an online parcel map for Meagher County?: Yes. A public source publishes a parcel map of 6,133 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Meagher County's boundary or name changed?: Meagher County was created in 1866 from Gallatin County. Since then the Atlas of Historical County Boundaries records 18 later changes, chiefly involving Cascade County, Gallatin County and Dawson County.
Is my lot in a flood zone?: We do not have flood maps for Meagher County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby