When was Dawson County founded?

Dawson County was founded in 1864, and named after Andrew Dawson.

What is the county seat of Dawson County?

The county seat of Dawson County is Glendive.

Is there an online parcel map for Dawson County?

Yes. A public source publishes a parcel map of 9,070 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Dawson County's boundary or name changed?

Dawson County was created in 1864. Since then the Atlas of Historical County Boundaries records 17 later changes, chiefly involving Custer County, Meagher County and Big Horn County.

Is my lot in a flood zone?

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

County · code 30021

Dawson CountyMontana

Dawson County is a county in Montana, with its seat in Glendive. It was created in 1864.

Founded1864
County seatGlendive
Named forAndrew Dawson
Land area2,372 sq mi + 12 sq mi water
Population8,940 2020 Census
Parcels mapped9,070 checked 14 October 2026

Open the free map Click any parcel in Dawson 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.

Dawson County was created by Idaho Territory on January 16, 1864, from non-county area. It became part of Montana Territory on May 26, 1864, but was eliminated in 1865 after losing all its territory. The county was re-created by Montana Territory on January 15, 1869, from what was then Big Horn County, now Custer County. After various boundary adjustments and attachments for judicial purposes over the following decades, Dawson County was fully organized and detached from Custer County on September 25, 1882.

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

1864
Dawson County created Dawson created by Idaho Territory from non-county area. 16 January 1864 · Idaho Terr. Laws 1863, 1st sess., sec. 7/p. 676
1864
Became part of Montana Dawson 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
Lost territory Dawson lost all territory to Big Horn (original, now Custer); Dawson eliminated.
to Big Horn to Custer
2 February 1865 · Mont. Terr. Laws 1864, 1st leg., sec. 9/p. 531
1869
Dawson County created Dawson re-created by Montana Territory from Big Horn (original, now Custer).
from Big Horn from Custer
15 January 1869 · Mont. Terr. Laws 1868, 5th leg., pp. 102-103
1889
Became part of Montana Dawson 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 20 changes (15 more)

1864
Dawson County created Dawson created by Idaho Territory from non-county area. 16 January 1864 · Idaho Terr. Laws 1863, 1st sess., sec. 7/p. 676
1864
Became part of Montana Dawson 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
Lost territory Dawson lost all territory to Big Horn (original, now Custer); Dawson eliminated.
to Big Horn to Custer
2 February 1865 · Mont. Terr. Laws 1864, 1st leg., sec. 9/p. 531
1869
Dawson County created Dawson re-created by Montana Territory from Big Horn (original, now Custer).
from Big Horn from Custer
15 January 1869 · Mont. Terr. Laws 1868, 5th leg., pp. 102-103
1872
Changed Dawson attached to Meagher "for judicial purposes."
Meagher
4 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585
1872
Boundary clarified Dawson boundaries redefined (no change).
no change
12 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 10/p. 432
1876
Lost territory Dawson lost to Meagher.
to Meagher
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."
Meagher Custer
19 February 1881 · Mont. Terr. Laws 1881, 12th leg., p. 122
1882
Changed Dawson fully organized, detached from Custer.
Custer
25 September 1882 · History of Montana 1739-1885, pp. 541-542
1883
Gained territory Dawson gained from Custer.
from Custer
8 March 1883 · Mont. Terr. Laws 1883, 13th leg., p. 99
1887
Boundary clarified Dawson boundaries redefined (no change).
no change
1 March 1887 · Mont. Terr. Laws 1887, 15th leg., sec. 739/p. 838
1889
Lost territory Dawson 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 Dawson 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 Dawson lost to creation of Valley. Act passed 6 February 1893; took effect 1 March 1893.
to Valley
1 March 1893 · Mont. Laws 1893, 3d leg., pp. 202-205
1914
Lost territory Dawson lost to creation of Richland.
to Richland
27 May 1914 · Minutes of Board of County Commissioners, Dawson County, 25-26 May 1914; Burlingame, 17-19
1914
Lost territory Dawson lost to creation of Wibaux.
to Wibaux
17 August 1914 · Minutes of Board of County Commissioners, Dawson County, 15 August 1914; Burlingame, 17-19
1915
Lost territory Dawson lost to creation of Prairie.
to Prairie
5 February 1915 · Minutes of Board of County Commissioners, Dawson County, 4 February 1915; Burlingame, 17-19
1917
Exchanged territory Dawson exchanged with Rosebud when their common boundary was placed on federal land survey lines.
with Rosebud
15 February 1917 · Mont. Laws 1917, 15th leg., ch. 36/pp. 38-39
1917
Lost territory Dawson lost small areas to Prairie and Wibaux when boundary was adjusted to run on federal land survey lines.
to Prairie to Wibaux
9 March 1917 · Mont. Laws 1917, 15th leg., ch. 139/pp. 232-235
1919
Lost territory Dawson lost to creation of Garfield and McCone. Garfield act passed 7 February 1919 and McCone act passed 20 February 1919; both acts took effect 1 April 1919.
to Garfield to McCone
1 April 1919 · Mont. Laws 1919, 16th leg., chs. 4, 33/pp. 3-8, 68-75

Land and parcels

What the maps cover in Dawson

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

Parcels Good enough

Lot lines and tax-map numbers for 9,070 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, 4,675 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

Dawson by the Census

Population

8,940 2020 Census count

Housing units

4,382 2020 Census count

Land area

2,372 square miles

Water area

12 square miles

People per sq mi

4 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

Dawson 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 Dawson County.
dawsoncountymontana.org

See your own lot on these maps

Open Dawson 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 Dawson County

When was Dawson County founded?: Dawson County was founded in 1864, and named after Andrew Dawson.
What is the county seat of Dawson County?: The county seat of Dawson County is Glendive.
Is there an online parcel map for Dawson County?: Yes. A public source publishes a parcel map of 9,070 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Dawson County's boundary or name changed?: Dawson County was created in 1864. Since then the Atlas of Historical County Boundaries records 17 later changes, chiefly involving Custer County, Meagher County and Big Horn County.
Is my lot in a flood zone?: We do not have flood maps for Dawson County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby