There are 29 counties in the U.S. state of Utah. There were originally seven counties established under the provisional State of Deseret in 1849: Davis, Iron, Sanpete, Salt Lake, Tooele, Utah, and Weber. The Territory of Utah was created in 1851 with the first territorial legislature meeting from 1851–1852. The first legislature re-created the original counties from the State of Deseret under territorial law as well as establishing three additional counties: Juab, Millard, and Washington. All other counties were established between 1854 and 1894 by the Utah Territorial Legislature under territorial law except for the last two counties formed, Daggett and Duchesne. They were created by popular vote and by gubernatorial proclamation after Utah became a state. Present-day Duchesne County encompassed an Indian reservation that was created in 1861. The reservation was opened to homesteaders in 1905 and the county was created in 1913. Due to dangerous roads, mountainous terrain, and bad weather preventing travel via a direct route, 19th century residents in present-day Daggett County had to travel 400 to 800 miles (640 to 1,290 km) on both stage and rail to conduct business in Vernal, the county seat for Uintah County a mere 50 miles (80 km) away. In 1917, all Uintah County residents voted to create Daggett County.

Based on 2022 United States Census data, the population of Utah was 3,417,734. Just over 75% of Utah's population is concentrated along four Wasatch Front counties: Salt Lake, Utah, Davis, and Weber. Salt Lake County was the largest county in the state with a population of 1,185,813, followed by Utah County with 719,174, Davis County with 373,207 and Weber County with 271,926. Daggett County was the least populated with 992 people. The largest county in land area is San Juan County with 7,821 square miles (20,260 km) and Davis County is the smallest with 304 square miles (790 km).

The Federal Information Processing Standard (FIPS) code, which is used by the United States government to uniquely identify states and counties, is provided with each county. Utah's FIPS code is 49, which when combined with any county code would be written as 49XXX. In the FIPS code column in the table below, each FIPS code links to the most current census data for that county.

The Utah Code (Title 17, Chapter 50, Part 5) divides the counties into six classes by population:

• First class: Population of 1,000,000 or more. Only one county - Salt Lake - is first class.
• Second class: Population between 175,000 and 1,000,000. Four counties.
• Third class: Population between 40,000 and 175,000. Five counties.
• Fourth class: Population between 11,000 and 40,000. Ten counties.
• Fifth class: Population between 4,000 and 11,000. Five counties.
• Sixth class: Population below 4,000. Four counties.

The county classes, for example, are used in the Utah legislature in crafting of legislation to distinguish between more urban and rural areas, such as important yet subtle distinctions in how revenue can be distributed. Usually, a bill intended to benefit rural counties would target the counties of the fourth, fifth and sixth class.

Under Utah Code (Title 17, Chapter 52a, Part 2), Utah counties are permitted to choose one of four forms of county government: a three-member full-time commission; a five or seven member expanded commission; a three to nine member (odd-numbered) part-time council with a full-time elected county mayor or a three to nine member (odd-numbered) part-time council with a full-time manager appointed by the council. 23 out of 29 counties are ruled by the standard three-member commission. Of the other six, Cache County was the first change in 1988 to a seven-member council with an elected mayor. Grand County adopted a seven-member council with appointed manager in 1992, followed by Morgan County in 1999 and Wasatch County in 2003. In 1998, Salt Lake County residents approved adopting a nine-member council with elected mayor that began work in 2001. Summit County adopted a five-member council with an appointed manager in 2006.

County	FIPS code	County seat	Est.	Origin	Etymology	Population	Area	Map
Beaver County	001	Beaver	January 5, 1856	Part of Iron County	The many beavers in the area	7,233	2,590 sq mi (6,708 km)
Box Elder County	003	Brigham City	January 5, 1856	Part of Weber County	The many Box Elder trees in the area	62,684	5,746 sq mi (14,882 km)
Cache County	005	Logan	January 5, 1857	Part of Weber County	Caches of furs made by Rocky Mountain Fur Company trappers	142,393	1,165 sq mi (3,017 km)
Carbon County	007	Price	March 8, 1894	Part of Emery County	The vast coal beds in the county	20,609	1,478 sq mi (3,828 km)
Daggett County	009	Manila	January 7, 1918	Part of Summit and Uintah counties	Oliver Ellsworth Daggett (1810–1880), the first Utah Surveyor General	992	697 sq mi (1,805 km)
Davis County	011	Farmington	October 5, 1850	Part of Deseret Great Salt Lake and Weber counties	Daniel C. Davis (1804–1850), Mormon Battalion captain	373,207	299 sq mi (774 km)
Duchesne County	013	Duchesne	January 4, 1915	Part of Wasatch County	Uncertain; likely origins are a Ute word translated "dark canyon", the French and Indian War site of Fort Duquesne (the county's initial settlement was also a fortress), the corrupted name of an area Indian chief, the name of Society of the Sacred Heart founder Rose Philippine Duchesne, the name of French geographer André Duchesne, or the name of French fur trapper and explorer Du Chasne	20,477	3,241 sq mi (8,394 km)
Emery County	015	Castle Dale	February 12, 1880	Part of Sanpete County	George W. Emery (1830–1909), Governor of the Utah Territory from 1875–1880	10,144	4,462 sq mi (11,557 km)
Garfield County	017	Panguitch	March 9, 1882	Part of Iron County	James A. Garfield (1831–1881), President of the United States in 1881	5,314	5,083 sq mi (13,165 km)
Grand County	019	Moab	March 13, 1890	Part of Emery County	The Grand River, since renamed to the Colorado River	9,706	3,672 sq mi (9,510 km)
Iron County	021	Parowan	January 31, 1850	Original county of State of Deseret	Iron mines west of Cedar City	64,211	3,297 sq mi (8,539 km)
Juab County	023	Nephi	March 3, 1852	Original county of Territory of Utah	A Native American word translated "thirsty valley" or "flat plain"	13,023	3,392 sq mi (8,785 km)
Kane County	025	Kanab	January 16, 1864	Part of Washington County	Thomas L. Kane (1822–1883), U.S. Army officer who spoke in favor of the Mormon migration and settlement of Utah	8,425	3,990 sq mi (10,334 km)
Millard County	027	Fillmore	October 4, 1851	Original county of Territory of Utah	Millard Fillmore (1800–1874), President of the United States from 1850 to 1853	13,437	6,572 sq mi (17,021 km)
Morgan County	029	Morgan	January 17, 1862	Part of Davis, Great Salt Lake, Summit, and Weber counties	Jedediah Morgan Grant (1816–1856), an Apostle of the Church of Jesus Christ of Latter-day Saints	13,000	609 sq mi (1,577 km)
Piute County	031	Junction	January 16, 1865	Part of Beaver County	The Piute tribe of Native Americans who lived in the area	1,550	758 sq mi (1,963 km)
Rich County	033	Randolph	January 16, 1864	Part of Cache County	Charles C. Rich (1809–1883), an Apostle of The Church of Jesus Christ of Latter-day Saints	2,670	1,029 sq mi (2,665 km)
Salt Lake County	035	Salt Lake City	January 31, 1850	Original county of State of Deseret	The Great Salt Lake, the largest terminal lake in the Western Hemisphere	1,185,813	742 sq mi (1,922 km)
San Juan County	037	Monticello	February 17, 1880	Parts of Kane, Iron, and Piute counties	Named for the San Juan River, a 400-mile (640 km) tributary of the Colorado river located in southern Colorado and Utah	14,358	7,820 sq mi (20,254 km)
Sanpete County	039	Manti	January 31, 1850	Original county of State of Deseret	Uncertain, possibly from a Ute Chief named San Pitch	30,277	1,590 sq mi (4,118 km)
Sevier County	041	Richfield	January 16, 1865	Part of Sanpete County	The Sevier River, a 280-mile (450 km) river in central Utah	22,344	1,911 sq mi (4,949 km)
Summit County	043	Coalville	January 13, 1854	Part of Great Salt Lake and Green River counties	High elevations in the county, which includes 39 of Utah's highest peaks	42,759	1,872 sq mi (4,848 km)
Tooele County	045	Tooele	January 31, 1850	Original county of State of Deseret	Uncertain, either from the Goshute Tribe Chief Tuilla or the Tules plant that grew in the marshes	82,051	6,941 sq mi (17,977 km)
Uintah County	047	Vernal	February 18, 1880	Part of Sanpete, Summit, and Wasatch counties	The Uintah band of the Ute tribe who lived in the area	37,747	4,480 sq mi (11,603 km)
Utah County	049	Provo	January 31, 1850	Original county of State of Deseret	Yuta, the Spanish name for the Ute tribe	719,174	2,003 sq mi (5,188 km)
Wasatch County	051	Heber City	January 17, 1862	Part of Great Salt Lake, Green River, Sanpete, Summit, and Utah counties	A Native American word meaning "mountain pass", also the name of the Wasatch Range	37,144	1,176 sq mi (3,046 km)
Washington County	053	St. George	March 3, 1852	Original county of Territory of Utah	George Washington (1732–1799), President of the United States from 1789 to 1797	202,452	2,426 sq mi (6,283 km)
Wayne County	055	Loa	March 10, 1892	Part of Piute County	Wayne County, Tennessee	2,614	2,461 sq mi (6,374 km)
Weber County	057	Ogden	January 31, 1850	Original county of State of Deseret	The Weber River, a 125 miles (201 km) tributary of the Great Salt Lake	271,926	576 sq mi (1,492 km)

• Great Salt Lake County – original county created January 31, 1850
• Iron County – original county created January 31, 1850
• Sanpete County – original county created January 31, 1850
• Tuilla County – original county created January 31, 1850
• Utah County – original county created January 31, 1850
• Weber County – original county created January 31, 1850
• Davis County – created October 5, 1850, from portions of Great Salt Lake County and Weber County

• Tuilla County, Deseret created January 31, 1850, re-created as Tooele County, Utah Territory on March 3, 1852.
• Great Salt Lake County, Utah Territory created March 3, 1852, name changed to Salt Lake County, Utah Territory on January 29, 1868
• Richland County, Utah Territory created January 16, 1854, name changed to Rich County, Utah Territory on January 29, 1868

There were ten counties in the Territory of Utah that were absorbed by other states or other Utah counties.

County	Established	Superseded	Etymology	Present location
Carson County	January 17, 1854	March 2, 1861	Named for Kit Carson, an American frontiersman	Nevada
Cedar County	January 5, 1856	January 17, 1862	Named for the numerous cedar trees growing in the area (which are actually juniper trees)	Utah County
Desert County	March 3, 1852	January 17, 1862	Named for the surrounding desert	Box Elder County, Tooele County and Nevada
Greasewood County	January 5, 1856	January 17, 1862	Named for the greasewood plant growing in the area	Box Elder County
Green River County	March 3, 1852	February 16, 1872	Named for the Green River, a 730-mile (1,170 km) tributary of the Colorado River that runs through Wyoming, Colorado and Utah	Cache, Weber, Morgan, Davis, Wasatch, Summit, Duchesne, Carbon, and Utah Counties, and Wyoming and Colorado
Humboldt County	January 5, 1856	March 2, 1861	Named for the Humboldt River, a 300-mile (480 km) river in Nevada and longest river in the Great Basin	Nevada
Malad County	January 5, 1856	January 17, 1862	Named for the Malad River, the name being French for "sickly"	Box Elder County
Rio Virgen County	February 18, 1869	February 16, 1872	Named for the Virgin River (el Rio de la Virgen), a 160-mile-long (260 km) tributary of the Colorado River located in southern Utah and Nevada	Washington County, Nevada and Arizona
St. Mary's County	January 5, 1856	January 17, 1862	Named after the Mary's River, which was later renamed to the Humboldt River	Nevada
Shambip County	January 12, 1856	January 17, 1862	Goshute Native American Tribe word for Rush Lake	Tooele County

• Van Cott, John W. (1990). Utah Place Names. Salt Lake City: University of Utah Press. ISBN 978-0-87480-345-7.

Media related to Counties of Utah at Wikimedia Commons