When was Madison County founded?

Madison County was founded in 1864, and named after James Madison.

What is the county seat of Madison County?

The county seat of Madison County is Virginia City.

Is there an online parcel map for Madison County?

Yes. A public source publishes a parcel map of 19,305 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Madison County's boundary or name changed?

Madison County was created in 1864. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Beaverhead County, Deer Lodge County and Gallatin County.

Is my lot in a flood zone?

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

County · code 30057

Madison CountyMontana

Madison County is a county in Montana with its seat in Virginia City, formed in 1864.

Founded1864
County seatVirginia City
Named forJames Madison
Land area3,588 sq mi + 15 sq mi water
Population8,623 2020 Census
Parcels mapped19,305 checked 14 October 2026

Open the free map Click any parcel in Madison 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.

Madison County was formed in 1864, and named after James Madison. Virginia City is the county seat.

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

1864
Madison County created Madison created by Idaho Territory from non-county area. 16 January 1864 · Idaho Terr. Laws 1863, 1st sess., sec. 4/p. 675
1865
Madison County created Madison re-created by Montana Territory; Madison lost to Beaverhead and Deer Lodge, and lost to creation of Gallatin.
from Beaverhead from Deer Lodge from Gallatin
2 February 1865 · Mont. Terr. Laws 1864, 1st leg., sec. 4/p. 529
1867
Gained territory Madison gained from Beaverhead, exchanged with Gallatin.
from Beaverhead from Gallatin
10 December 1867 · Mont. Terr. Laws 1867, 4th leg., sec. 3/p. 103
1867
Gained territory Madison gained from Deer Lodge.
from Deer Lodge
23 December 1867 · Mont. Terr. Laws 1867, 4th leg., pp. 129-130
1889
Became part of Montana Madison 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 13 changes (8 more, mostly small adjustments)

1864
Madison County created Madison created by Idaho Territory from non-county area. 16 January 1864 · Idaho Terr. Laws 1863, 1st sess., sec. 4/p. 675
1864
Lost territory Madison lost small area of about two square miles to Dakota Territory when Dakota Territory gained from Idaho Territory. Madison 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
Madison County created Madison re-created by Montana Territory; Madison lost to Beaverhead and Deer Lodge, and lost to creation of Gallatin.
from Beaverhead from Deer Lodge from Gallatin
2 February 1865 · Mont. Terr. Laws 1864, 1st leg., sec. 4/p. 529
1866
Boundary clarified Madison boundaries redefined (no change). Acts of the 2d and 3d legislatures were declared null and void by the United States Congress, 2 March 1867.
no change
28 March 1866 · Mont. Terr. Laws 1866, 2d leg., ch. 22/pp. 25-26; 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 Madison gained from Beaverhead, exchanged with Gallatin.
from Beaverhead from Gallatin
10 December 1867 · Mont. Terr. Laws 1867, 4th leg., sec. 3/p. 103
1867
Gained territory Madison gained from Deer Lodge.
from Deer Lodge
23 December 1867 · Mont. Terr. Laws 1867, 4th leg., pp. 129-130
1869
Gained territory Madison gained from Beaverhead and Deer Lodge.
from Beaverhead from Deer Lodge
12 January 1869 · Mont. Terr. Laws 1868, 5th leg., p. 105
1872
Boundary clarified Madison boundaries redefined (no change).
no change
12 January 1872 · Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 4/p. 430
1874
Changed Madison authorized to gain part of the remnant of Dakota Territory which was transferred to Montana Territory on 17 February 1873. This act appears to have been based on faulty maps, since the area was actually surrounded by Gallatin (no change).
Gallatin
7 February 1874 · Mont. Terr. Laws 1874, 8th leg., p. 68; Van Zandt, 136, 145, 150; De Lacy, Map of the Territory of Montana
1887
Boundary clarified Madison boundaries redefined (no change).
no change
1 March 1887 · Mont. Terr. Laws 1887, 15th leg., sec. 733/pp. 834-835
1889
Became part of Montana Madison 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 Madison lost to Beaverhead.
to Beaverhead
2 March 1911 · Mont. Laws 1911, 12th leg., ch. 73/pp. 137-141
1913
Exchanged territory Madison exchanged with Gallatin when boundary was adjusted to run on federal land survey lines.
with Gallatin
8 March 1913 · Mont. Laws 1913, 13th leg., ch. 60/pp. 113-116

Land and parcels

What the maps cover in Madison

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

Parcels Good enough

Lot lines and tax-map numbers for 19,305 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, 10,387 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

Madison by the Census

Population

8,623 2020 Census count

Housing units

6,379 2020 Census count

Land area

3,588 square miles

Water area

15 square miles

People per sq mi

2 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

Madison 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 Madison County.
madison.mt.gov

See your own lot on these maps

Open Madison 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 Madison County

When was Madison County founded?: Madison County was founded in 1864, and named after James Madison.
What is the county seat of Madison County?: The county seat of Madison County is Virginia City.
Is there an online parcel map for Madison County?: Yes. A public source publishes a parcel map of 19,305 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Madison County's boundary or name changed?: Madison County was created in 1864. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Beaverhead County, Deer Lodge County and Gallatin County.
Is my lot in a flood zone?: We do not have flood maps for Madison County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby