When was Fergus County founded?

Fergus County was founded in 1886, formed from Meagher County, and named after James Fergus.

What is the county seat of Fergus County?

The county seat of Fergus County is Lewistown.

Is there an online parcel map for Fergus County?

Yes. A public source publishes a parcel map of 20,840 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Fergus County's boundary or name changed?

Fergus County was created in 1886 from Meagher County. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Chouteau County, Judith Basin County and Meagher County.

Is my lot in a flood zone?

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

County · code 30027

Fergus CountyMontana

Fergus County is a county in Montana, with its seat in Lewistown, formed in 1886 from Meagher County.

Founded1886
County seatLewistown
Named forJames Fergus
Land area4,339 sq mi + 11 sq mi water
Population11,446 2020 Census
Parcels mapped20,840 checked 14 October 2026

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

Updated 20 October 2026

Census outline · seat marked

History

Formed in 1886 from Meagher County

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

Fergus County was formed in 1886 from Meagher County, and named after James Fergus. Lewistown is the county seat.

Deeds and plats from before 1886 for land now in Fergus County may have been recorded in Meagher County.

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

1886
Fergus County created Fergus created by Montana Territory from Meagher. Act passed 12 March 1885; took effect 1 December 1886.
from Meagher
1 December 1886 · Mont. Terr. Laws 1885, 14th leg., pp. 78-83
1889
Gained territory Fergus gained from Choteau (now Chouteau) and Dawson. Act passed 14 March 1889; took effect 1 April 1889.
from Choteau from Chouteaufrom Dawson
1 April 1889 · Mont. Terr. Laws 1889, 16th leg., pp. 232-233
1889
Became part of Montana Fergus 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
1911
Lost territory Fergus lost to creation of Musselshell and lost to Meagher. Act passed 11 February 1911; took effect 1 March 1911.
to Musselshell to Meagher
1 March 1911 · Mont. Laws 1911, 12th leg., ch. 25/pp. 29-38
1920
Lost territory Fergus lost to creation of Judith Basin.
to Judith Basin
10 December 1920 · Mont. Rev. Code 1921, sec. 4327/pp. 1584-1586; Burlingame, 17-20

Show all 12 changes (7 more, mostly small adjustments)

1886
Fergus County created Fergus created by Montana Territory from Meagher. Act passed 12 March 1885; took effect 1 December 1886.
from Meagher
1 December 1886 · Mont. Terr. Laws 1885, 14th leg., pp. 78-83
1887
Boundary clarified Fergus boundaries redefined (no change).
no change
1 March 1887 · Mont. Terr. Laws 1887, 15th leg., sec. 743/p. 840
1887
Lost territory Fergus lost small area to creation of Cascade and exchanged with Meagher. Act passed 12 September 1887; took effect 19 December 1887.
to Cascade to Meagher
19 December 1887 · Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105-109
1889
Gained territory Fergus gained from Choteau (now Chouteau) and Dawson. Act passed 14 March 1889; took effect 1 April 1889.
from Choteau from Chouteaufrom Dawson
1 April 1889 · Mont. Terr. Laws 1889, 16th leg., pp. 232-233
1889
Became part of Montana Fergus 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
1907
Boundary clarified Fergus boundaries redefined to correct oversight in Montana Political Code of 1895 (no change).
no change
21 February 1907 · Mont. Laws 1907, 10th leg., ch. 28/pp. 49-50
1911
Lost territory Fergus lost to creation of Musselshell and lost to Meagher. Act passed 11 February 1911; took effect 1 March 1911.
to Musselshell to Meagher
1 March 1911 · Mont. Laws 1911, 12th leg., ch. 25/pp. 29-38
1920
Lost territory Fergus lost to creation of Judith Basin.
to Judith Basin
10 December 1920 · Mont. Rev. Code 1921, sec. 4327/pp. 1584-1586; Burlingame, 17-20
1921
Gained territory Fergus gained small area from Chouteau when boundary was redefined to run on federal land survey lines.
from Chouteau
1 June 1921 · Mont. Rev. Code 1921, sec. 4318/p. 1575
1925
Lost territory Fergus lost to creation of Petroleum.
to Petroleum
22 February 1925 · Mont. Laws 1925, 19th leg., pp. 505-508
1925
Lost territory Fergus lost to Judith Basin.
to Judith Basin
10 March 1925 · Mont. Laws 1925, 19th leg., ch. 93/pp. 125-130; "State ex rel. Foot v. Burr et al.," in Mont. Rpts., 73: 586-590
1951
Boundary clarified Fergus boundaries redefined to correct mistake in the 1935 and 1947 Revised Codes of Montana (no change).
no change
1 March 1951 · Mont. Laws 1951, 32d leg., ch. 173/pp. 342-349

Land and parcels

What the maps cover in Fergus

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

Parcels Good enough

Lot lines and tax-map numbers for 20,840 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 14 October 2026
Address points Official

One point per address, 8,637 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

Fergus by the Census

Population

11,446 2020 Census count

Housing units

6,013 2020 Census count

Land area

4,339 square miles

Water area

11 square miles

People per sq mi

3 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

Fergus 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 Fergus County.
fergusmt.gov

See your own lot on these maps

Open Fergus 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 Fergus County

When was Fergus County founded?: Fergus County was founded in 1886, formed from Meagher County, and named after James Fergus.
What is the county seat of Fergus County?: The county seat of Fergus County is Lewistown.
Is there an online parcel map for Fergus County?: Yes. A public source publishes a parcel map of 20,840 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Fergus County's boundary or name changed?: Fergus County was created in 1886 from Meagher County. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Chouteau County, Judith Basin County and Meagher County.
Is my lot in a flood zone?: We do not have flood maps for Fergus County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby