The largest county in North Dakota

There are two right answers. By land area it is McKenzie County; by population it is Cass County. Which one you want depends on what you meant by largest.

Largest by land area

McKenzie County

2,760 sq mi

4.0% of North Dakota's land

Largest by population

Cass County

201,794 people

25.2% of North Dakota's population

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025. Retrieved 30 August 2026.

By land area

The ten largest counties of North Dakota by land area. Land area excludes inland and coastal water.
RankNameLand areaPopulation
1McKenzie County2,760 sq mi15,192
2Stutsman County2,222 sq mi21,414
3McLean County2,110 sq mi9,740
4Williams County2,078 sq mi41,767
5Ward County2,013 sq mi68,233
6Dunn County2,008 sq mi4,058
7Morton County1,926 sq mi34,601
8McHenry County1,874 sq mi5,130
9Mountrail County1,825 sq mi9,395
10Cass County1,765 sq mi201,794

By population

The ten most populous counties of North Dakota, from the Census Bureau's Vintage 2025 estimates.
RankNamePopulationDensity
1Cass County201,794114 per sq mi
2Burleigh County103,25163.2 per sq mi
3Grand Forks County74,50151.9 per sq mi
4Ward County68,23333.9 per sq mi
5Williams County41,76720.1 per sq mi
6Morton County34,60118.0 per sq mi
7Stark County34,01325.5 per sq mi
8Stutsman County21,4149.6 per sq mi
9Richland County16,73111.7 per sq mi
10McKenzie County15,1925.5 per sq mi

And the smallest

Smallest by land area

Eddy County

630.2 sq mi

Least populous

Slope County

628 people

More on North Dakota

Rebuilt from source data 30 August 2026. How these figures are produced.