When was Traill County founded?

Traill County was founded in 1875.

What is the county seat of Traill County?

The county seat of Traill County is Hillsboro.

Is there an online parcel map for Traill County?

Yes. State of North Dakota GIS Hub (NDIT; State Parcel Program, counties as custodians) publishes a parcel map of 10,609 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Traill County's boundary or name changed?

Atlas of Historical County Boundaries records 2 changes for Traill County. Since then the Atlas of Historical County Boundaries records 2 later changes, chiefly involving Steele County.

Who issues building permits in Traill County?

The county's page on building permits: Permits. Inside a city or town, ask that city first.

Who issues septic and well permits in Traill County?

The county's page on septic systems and wells: Board of Health.

Is my lot in a flood zone?

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

County · code 38097

Traill CountyNorth Dakota

Traill County is a county in North Dakota with its seat in Hillsboro. The county was formed in 1875 and became part of the state of North Dakota in 1889.

Founded1875
County seatHillsboro
Land area862 sq mi + 0.6 sq mi water
Population7,997 2020 Census
Parcels mapped10,609 checked 14 October 2026

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

Updated 20 October 2026

Census outline · seat marked

History

Founded in 1875

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

Traill County was formed in 1875 in Dakota Territory. In 1883, Steele County was created from Traill County's territory. Traill became a county in the state of North Dakota on November 2, 1889.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries.

1883
Lost territory Traill lost to creation of Steele.
to Steele
2 June 1883 · Dak. Terr. Laws 1883, 15th sess., ch. 36/p. 52
1889
Became part of North Dakota Traill became a county in the state of North Dakota. 2 November 1889 · U.S. Stat., vol. 25, ch. 180[1889]/pp. 676-684 and vol. 26, no. 5/pp. 1548-1549; Swindler, 7:526-527; Van Zandt, 134

Land and parcels

What the maps cover in Traill

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

Parcels Good enough

Lot lines and tax-map numbers for 10,609 parcels from State of North Dakota GIS Hub (NDIT; State Parcel Program, counties as custodians). Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 12 October 2026 · checked 14 October 2026
Address points Official

One point per address, 4,466 in all from State of North Dakota — NDGISHUB / ND Department of Emergency Services (owner NDGISHDP-DES).
edited 12 October 2026 · checked 13 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

Traill by the Census

Population

7,997 2020 Census count

Housing units

3,649 2020 Census count

Land area

862 square miles

Water area

0.6 square miles

People per sq mi

9 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

Assessor and property records
Taxation
from co.traill.nd.us · checked 13 October 2026
Clerk of court: deeds and plats
Clerk of Court
from co.traill.nd.us · checked 13 October 2026

Permits

Health department: septic and well
Board of Health
from co.traill.nd.us · checked 13 October 2026
Permitsfrom co.traill.nd.us
Building Permitsfrom co.traill.nd.us

County government

County government
The official website of Traill County.
co.traill.nd.us

See your own lot on these maps

Open Traill 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 Traill County

When was Traill County founded?: Traill County was founded in 1875.
What is the county seat of Traill County?: The county seat of Traill County is Hillsboro.
Is there an online parcel map for Traill County?: Yes. State of North Dakota GIS Hub (NDIT; State Parcel Program, counties as custodians) publishes a parcel map of 10,609 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Traill County's boundary or name changed?: Atlas of Historical County Boundaries records 2 changes for Traill County. Since then the Atlas of Historical County Boundaries records 2 later changes, chiefly involving Steele County.
Who issues building permits in Traill County?: The county's page on building permits: Permits. Inside a city or town, ask that city first.
Who issues septic and well permits in Traill County?: The county's page on septic systems and wells: Board of Health.
Is my lot in a flood zone?: We do not have flood maps for Traill County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby