When was Chouteau County founded?

Chouteau County was founded in 1864, and named after Pierre Chouteau Jr..

What is the county seat of Chouteau County?

The county seat of Chouteau County is Fort Benton.

Is there an online parcel map for Chouteau County?

Yes. A public source publishes a parcel map of 14,289 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Chouteau County's boundary or name changed?

Chouteau County was created in 1864. Since then the Atlas of Historical County Boundaries records 23 later changes, chiefly involving Cascade County, Lewis and Clark County and Fergus County.

Is my lot in a flood zone?

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

County · code 30015

Chouteau CountyMontana

Chouteau County is a county in north-central Montana, with its county seat at Fort Benton. It was created on January 16, 1864, by Idaho Territory and named after Pierre Chouteau Jr.

Founded1864
County seatFort Benton
Named forPierre Chouteau Jr.
Land area3,973 sq mi + 24 sq mi water
Population5,895 2020 Census
Parcels mapped14,289 checked 14 October 2026

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

Updated 20 October 2026

Census outline · seat marked

History

Founded in 1864

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

Chouteau County was established by Idaho Territory on January 16, 1864, and transferred to Montana Territory in May 1864. The county was re-created by Montana Territory in February 1865 after being partially transferred to create other counties, and it experienced multiple boundary changes over the following years.

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

1864
Chouteau County created Choteau (now Chouteau) created by Idaho Territory from non-county area. 16 January 1864 · Idaho Terr. Laws 1863, 1st sess., sec. 6/p. 676
1864
Became part of Montana Choteau (now Chouteau) became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. 26 May 1864 · U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145
1865
Chouteau County created Choteau (now Chouteau) re-created by Montana Territory; Choteau lost to creation of Edgerton (now Lewis and Clark).
from Edgertonfrom Lewis and Clark
2 February 1865 · Mont. Terr. Laws 1864, 1st leg., sec. 8/p. 531
1866
Lost territory Choteau (now Chouteau) lost to creation of Musselshell (original). Acts of the 2d and 3d legislatures were declared null and void by the United States Congress, 2 March 1867.
to Musselshell
10 April 1866 · Mont. Terr. Laws 1866, 2d leg., ch. 4/p. 6; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219-228; Sanders, Helen F., 1:331-341
1889
Became part of Montana Choteau (now Chouteau) 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 26 changes (21 more)

1864
Chouteau County created Choteau (now Chouteau) created by Idaho Territory from non-county area. 16 January 1864 · Idaho Terr. Laws 1863, 1st sess., sec. 6/p. 676
1864
Became part of Montana Choteau (now Chouteau) became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. 26 May 1864 · U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145
1865
Chouteau County created Choteau (now Chouteau) re-created by Montana Territory; Choteau lost to creation of Edgerton (now Lewis and Clark).
from Edgertonfrom Lewis and Clark
2 February 1865 · Mont. Terr. Laws 1864, 1st leg., sec. 8/p. 531
1866
Lost territory Choteau (now Chouteau) lost to creation of Musselshell (original). Acts of the 2d and 3d legislatures were declared null and void by the United States Congress, 2 March 1867.
to Musselshell
10 April 1866 · Mont. Terr. Laws 1866, 2d leg., ch. 4/p. 6; 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
Gained territory Choteau (now Chouteau) gained part of Musselshell (original); Musselshell eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory.
from Musselshell
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
Lost territory Choteau (now Chouteau) lost to re-creation of Meagher.
to Meagher
16 November 1867 · Mont. Terr. Laws 1867, 4th leg., pp. 99-100
1867
Changed Part of Choteau (now Chouteau) reverted to non-county area. 12 December 1867 · Mont. Terr. Laws 1867, 4th leg., p. 129
1872
Changed Choteau (now Chouteau) attached to Lewis and Clark "for judicial purposes."
Lewis and Clark
4 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585
1872
Boundary clarified Choteau (now Chouteau) boundaries redefined (no change).
no change
12 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 9/pp. 431-432
1876
Gained territory Choteau (now Chouteau) gained from Big Horn (original, now Custer) and Deer Lodge.
from Big Horn from Custer from Deer Lodge
5 February 1876 · Mont. Terr. Laws 1876, 9th leg., pp. 46-47
c. 1879
Changed Choteau (now Chouteau) fully organized, detached from Lewis and Clark.
Lewis and Clark
31 December 1879 · History of Montana 1739-1885, p. 494
1887
Boundary clarified Choteau (now Chouteau) boundaries redefined (no change).
no change
1 March 1887 · Mont. Terr. Laws 1887, 15th leg., sec. 738/pp. 837-838
1887
Lost territory Choteau (now Chouteau) lost to creation of Cascade; Cascade not fully organized, attached to Choteau "for judicial purposes." Act passed 12 September 1887; took effect 19 December 1887.
to Cascade
19 December 1887 · Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105-109
1888
Changed Cascade fully organized, detached from Choteau (now Chouteau).
Cascade
1 February 1888 · Mont. Terr. Laws 1887, 15th leg., ext. sess., sec. 13/p. 109
1889
Lost territory Choteau (now Chouteau) lost to Fergus. Act passed 14 March 1889; took effect 1 April 1889.
to Fergus
1 April 1889 · Mont. Terr. Laws 1889, 16th leg., pp. 232-233
1889
Became part of Montana Choteau (now Chouteau) 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
1893
Lost territory Choteau (now Chouteau) lost to creation of Teton. Act passed 7 February 1893; took effect 1 March 1893.
to Teton
1 March 1893 · Mont. Laws 1893, 3d leg., pp. 205-209
1903
Lost territory Choteau (now Chouteau) lost to Cascade.
to Cascade
3 March 1903 · Mont. Laws 1903, 8th leg., ch. 51/pp. 111-112
1903
Changed Spelling of "Choteau" changed to "Chouteau."
Choteau
5 March 1903 · Mont. Laws 1903, 8th leg., ch. 74/p. 147
1912
Lost territory Chouteau lost to creation of Hill.
to Hill
28 February 1912 · Map of Hill County, 1912; Burlingame, 17-18
1912
Lost territory Chouteau lost to creation of Blaine.
to Blaine
29 February 1912 · Mont. Rev. Code 1921, sec. 4307/pp. 1557-1559; Burlingame, 17-18
1919
Lost territory Chouteau lost to creation of Pondera. Act passed 17 February 1919; took effect 1 April 1919.
to Pondera
1 April 1919 · Mont. Laws 1919, 16th leg., ch. 22/pp. 38-45
1920
Lost territory Chouteau lost to creation of Liberty.
to Liberty
11 February 1920 · Mont. Rev. Code 1921, sec. 4329/pp. 1587-1588; Burlingame, 17-20
1920
Lost territory Chouteau lost small area to creation of Judith Basin when boundary was defined in terms of the federal land survey lines.
to Judith Basin
10 December 1920 · Mont. Rev. Code 1921, sec. 4327/pp. 1584-1586; Burlingame, 17-20
1921
Lost territory Chouteau lost to Teton.
to Teton
5 March 1921 · Mont. Laws 1921, 17th leg., ch. 174/pp. 326-329
1921
Lost territory Chouteau lost small area to Fergus when southern boundary was redefined to run on federal land survey lines.
to Fergus
1 June 1921 · Mont. Rev. Code 1921, sec. 4312/pp. 1564-1565

Land and parcels

What the maps cover in Chouteau

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

Parcels Good enough

Lot lines and tax-map numbers for 14,289 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, 4,116 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

Chouteau by the Census

Population

5,895 2020 Census count

Housing units

2,843 2020 Census count

Land area

3,973 square miles

Water area

24 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

Chouteau 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 Chouteau County.
co.chouteau.mt.us

See your own lot on these maps

Open Chouteau 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 Chouteau County

When was Chouteau County founded?: Chouteau County was founded in 1864, and named after Pierre Chouteau Jr..
What is the county seat of Chouteau County?: The county seat of Chouteau County is Fort Benton.
Is there an online parcel map for Chouteau County?: Yes. A public source publishes a parcel map of 14,289 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Chouteau County's boundary or name changed?: Chouteau County was created in 1864. Since then the Atlas of Historical County Boundaries records 23 later changes, chiefly involving Cascade County, Lewis and Clark County and Fergus County.
Is my lot in a flood zone?: We do not have flood maps for Chouteau County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby