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County · code 30017

Custer CountyMontana

Custer County is a county in Montana with its seat in Miles City, created in 1864.

  • Founded1864
  • County seatMiles City
  • Named forGeorge Armstrong Custer
  • Land area3,783 sq mi + 9.9 sq mi water
  • Population11,867 2020 Census
  • Parcels mapped12,019 checked 16 October 2026
Open the free map Click any parcel in Custer County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated

PrairiePowder RiverFallonRosebudCarter Miles City Census outline · seat marked

Where it is

Custer on the map of Montana

Montana has 56 counties and county equivalents, each with its own records office. Shapes with a page are links.

Beaverhead CountyBig Horn CountyBlaine CountyBroadwater CountyCarbon CountyCarter CountyCascade CountyChouteau CountyDaniels CountyDawson CountyDeer Lodge CountyFallon CountyFergus CountyFlathead CountyGallatin CountyGarfield CountyGlacier CountyGolden Valley CountyGranite CountyHill CountyJefferson CountyJudith Basin CountyLake CountyLewis and Clark CountyLiberty CountyLincoln CountyMcCone CountyMadison CountyMeagher CountyMineral CountyMissoula CountyMusselshell CountyPark CountyPetroleum CountyPhillips CountyPondera CountyPowder River CountyPowell CountyPrairie CountyRavalli CountyRichland CountyRoosevelt CountyRosebud CountySanders CountySheridan CountySilver Bow CountyStillwater CountySweet Grass CountyTeton CountyToole CountyTreasure CountyValley CountyWheatland CountyWibaux CountyYellowstone CountyCuster County Custer
Counties of Montana · Custer highlighted

History

Founded in 1864

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

Originally called Big Horn County when created by Idaho Territory on January 16, 1864, it became part of Montana Territory in May 1864. The county was renamed Custer on February 16, 1877. Custer County was named after George Armstrong Custer.

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

  1. 1864
    Custer County created Big Horn (original, now Custer) created by Idaho Territory from non-county area. · Idaho Terr. Laws 1863, 1st sess., sec. 8/pp. 676-677
  2. 1864
    Became part of Montana Big Horn (original, now Custer) 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. · U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145
  3. 1865
    Custer County created Big Horn (original, now Custer) re-created by Montana Territory. Big Horn gained all of Dawson; Dawson eliminated. Big Horn not fully organized, attached to Gallatin "for legislative and judicial purposes."
    from Dawsonfrom Gallatin
    · Mont. Terr. Laws 1864, 1st leg., sec. 9/p. 531
  4. 1877
    Renamed Big Horn (original) renamed Custer.
    formerly Big Horn
    · Mont. Terr. Laws 1877, 10th leg., p. 425
  5. 1889
    Became part of Montana Custer became a county in the state of Montana. · U.S. Stat., vol. 26, pp. 1551-1552 and vol. 25, ch. 180 [1889]/pp. 676-684; Swindler, 6:82-83
Show all 27 changes (22 more)
  1. 1864
    Custer County created Big Horn (original, now Custer) created by Idaho Territory from non-county area. · Idaho Terr. Laws 1863, 1st sess., sec. 8/pp. 676-677
  2. 1864
    Became part of Montana Big Horn (original, now Custer) 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. · U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145
  3. 1865
    Custer County created Big Horn (original, now Custer) re-created by Montana Territory. Big Horn gained all of Dawson; Dawson eliminated. Big Horn not fully organized, attached to Gallatin "for legislative and judicial purposes."
    from Dawsonfrom Gallatin
    · Mont. Terr. Laws 1864, 1st leg., sec. 9/p. 531
  4. 1866
    Lost territory Big Horn (original, now Custer) 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
    · 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
  5. 1867
    Gained territory Big Horn (original, now Custer) 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
    · U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219-228; Sanders, Helen F., 1:331-341
  6. 1869
    Lost territory Big Horn (original, now Custer) lost to creation of Dawson.
    to Dawson
    · Mont. Terr. Laws 1868, 5th leg., pp. 102-103
  7. 1872
    Changed Attachment of Big Horn (original, now Custer) to Gallatin "for judicial purposes" was confirmed.
    Gallatin
    · Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585
  8. 1872
    Gained territory Big Horn (original, now Custer) gained from Gallatin and gained non-county area (1), formerly part of Choteau (now Chouteau). Big Horn remained attached to Gallatin "for legislative and judicial purposes."
    from Gallatinfrom Choteaufrom Chouteau
    · Mont. Terr. Laws 1871, 7th leg., ch. 20, secs. 8, 11/pp. 431-432
  9. 1876
    Lost territory Big Horn (original, now Custer) lost to Choteau (now Chouteau).
    to Choteauto Chouteau
    · Mont. Terr. Laws 1876, 9th leg., p. 47
  10. 1876
    Lost territory Big Horn (original, now Custer) lost to Meagher.
    to Meagher
    · Mont. Terr. Laws 1876, 9th leg., p. 48
  11. 1877
    Renamed Big Horn (original) renamed Custer.
    formerly Big Horn
    · Mont. Terr. Laws 1877, 10th leg., p. 425
  12. 1877
    Changed Custer fully organized, detached from Gallatin.
    Gallatin
    · History of Montana 1739-1885, p. 517
  13. 1881
    Changed Dawson detached from Meagher, attached to Custer "for judicial and other purposes."
    DawsonMeagher
    · Mont. Terr. Laws 1881, 12th leg., p. 122
  14. 1882
    Lost territory Custer lost to Gallatin. The area included all territory ceded by the Crow Indians to the United States on 12 June 1880; the United States Congress ratified the cession on 11 April 1882. Montana Territorial Legislature passed this act 14 February 1881 to take effect upon ratification of the treaty by the U. S. Congress.
    to Gallatinto U. S.
    · Mont. Terr. Laws 1881, 12th leg., p. 124; Royce, 900-901, 904-905, pl. 39
  15. 1882
    Changed Dawson fully organized, detached from Custer.
    Dawson
    · History of Montana 1739-1885, pp. 541-542
  16. 1883
    Lost territory Custer lost to creation of Yellowstone; Yellowstone not fully organized, attached to Custer "for judicial purposes."
    to Yellowstone
    · Mont. Terr. Laws 1883, 13th leg., pp. 119-122
  17. 1883
    Lost territory Custer lost to Dawson.
    to Dawson
    · Mont. Terr. Laws 1883, 13th leg., p. 99
  18. 1883
    Changed Yellowstone fully organized, detached from Custer.
    Yellowstone
    · Mont. Terr. Laws 1883, 13th leg., sec. 11/p. 122
  19. 1885
    Lost territory Custer lost part of the Crow Indian reservation, which was attached as a non-county area (2) to Yellowstone "for judicial purposes."
    to Yellowstone
    · Mont. Terr. Laws 1885, 14th leg., p. 74
  20. 1887
    Boundary clarified Custer boundaries redefined (no change).
    no change
    · Mont. Terr. Laws 1887, 15th leg., secs. 740, 742/pp. 838, 839-840
  21. 1889
    Became part of Montana Custer became a county in the state of Montana. · U.S. Stat., vol. 26, pp. 1551-1552 and vol. 25, ch. 180 [1889]/pp. 676-684; Swindler, 6:82-83
  22. 1901
    Lost territory Custer lost to creation of Rosebud. Act passed 11 February 1901; took effect 1 March 1901.
    to Rosebud
    · Mont. Laws 1901, 7th leg., pp. 97-101
  23. 1913
    Lost territory Custer lost to creation of Fallon.
    to Fallon
    · Minutes of Board of County Commissioners, Custer County, 2 December 1913; Burlingame, 17-19
  24. 1915
    Lost territory Custer lost to creation of Prairie.
    to Prairie
    · Minutes of Board of County Commissioners, Dawson County, 4 February 1915; Burlingame, 17-19
  25. 1917
    Lost territory Custer lost to Prairie.
    to Prairie
    · Mont. Laws 1917, 15th leg., ch. 139/pp. 232-235
  26. 1919
    Lost territory Custer lost to creation of Powder River. Act passed 7 March 1919; took effect 1 April 1919.
    to Powder River
    · Mont. Laws 1919, 16th leg., ch. 141/pp. 277-282
  27. 1921
    Gained territory Custer gained small area from Prairie when boundary was adjusted to run on federal land survey lines.
    from Prairie
    · Mont. Rev. Code 1921, sec. 4313/pp. 1566-1567

Land and parcels

What the maps cover in Custer

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

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

Custer by the Census

Population
11,867 2020 Census count
Housing units
5,776 2020 Census count
Land area
3,783 square miles
Water area
9.9 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

Who to ask before you build, dig or sell

Official county pages only. We link to them; we do not copy them, because they change.

Inside a city or town, permits usually come from that city rather than the county.

Records

Permits

Zoning and code

County government

See your own lot on these maps

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Questions

Common questions about Custer County

When was Custer County founded?
Custer County was founded in 1864, and named after George Armstrong Custer.
What is the county seat of Custer County?
The county seat of Custer County is Miles City.
Is there an online parcel map for Custer County?
Yes. Montana State Library (Montana Cadastral Framework; data from MT Dept of Revenue ORION and five counties) publishes a parcel map of 12,019 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Custer County's boundary or name changed?
Custer County was created in 1864. Since then the Atlas of Historical County Boundaries records 25 later changes, chiefly involving Dawson County, Gallatin County and Prairie County. It was formerly called Big Horn.
Who issues building permits in Custer County?
The county's page on building permits: Concealed Weapons Permit. Inside a city or town, ask that city first.
Who issues septic and well permits in Custer County?
The county's page on septic systems and wells: Health department: septic and well.
Is my lot in a flood zone?
We do not have flood maps for Custer County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby

Counties next door