Originally part of Mexico, Arizona became a U.S. territory after the Mexican-American War and achieved statehood in 1912. It’s known for Native American heritage and landmarks like the Grand Canyon. Arizona has 15 counties.
10 Largest Counties in Arizona
1. Maricopa County
County Facts
- Population: 4,507,419 (2020 Census)
- Area Codes: 602, 480, 623
- ZIP Codes: 85001-85392
- County Seat: Phoenix
Geography and History
Maricopa County, located in central Arizona, spans 9,224 square miles, making it the state’s most populous county and one of the largest by area. Its geography consists of desert plains and mountain ranges, including the Phoenix Mountains and South Mountain. Established in 1871, Maricopa County’s history is rooted in the Hohokam people, who created extensive irrigation systems in the Salt River Valley. Phoenix became the county seat in 1877 and eventually grew into the state capital. The development of canals and agriculture, followed by the rise of manufacturing and technology industries, fueled the county’s rapid growth in the 20th century. Today, Maricopa County is a major urban center with a diverse economy.
Colleges and Universities
- Arizona State University (ASU): One of the largest public universities in the U.S., with campuses in Tempe, Phoenix, and other areas.
- Grand Canyon University: A private Christian university offering a wide range of undergraduate and graduate programs.
- Maricopa Community Colleges: A network of 10 community colleges offering vocational training and associate degrees.
- University of Phoenix: A for-profit institution offering online and in-person degree programs, headquartered in Phoenix.
Major Landmarks
Maricopa County is home to iconic landmarks such as Camelback Mountain, a popular hiking spot offering panoramic views of the Phoenix Valley. Papago Park includes the Desert Botanical Garden and the Phoenix Zoo. The Heard Museum showcases Native American art and history, while the Musical Instrument Museum is an internationally recognized cultural attraction. South Mountain Park and Preserve, one of the largest urban parks in the country, offers miles of trails. Chase Field and State Farm Stadium are major sports venues, hosting the Arizona Diamondbacks and Arizona Cardinals, respectively.
2. Pima County
County Facts
- Population: 1,043,433 (2020 Census)
- Area Codes: 520
- ZIP Codes: 85601-85775
- County Seat: Tucson
Geography and History
Pima County, located in southern Arizona, covers 9,189 square miles and features diverse geography, from desert landscapes to mountain ranges like the Santa Catalina Mountains. The county was named after the indigenous Pima people and was established in 1864, one of the four original counties of the Arizona Territory. Tucson, the county seat, was founded in 1775 as a Spanish fort and grew into a vital frontier town during the 19th century. The region’s history includes Spanish colonization, Mexican rule, and eventual American acquisition after the Gadsden Purchase in 1854. Pima County’s economy today is driven by education, tourism, and defense, with a strong connection to the University of Arizona.
Colleges and Universities
- University of Arizona (UA): A public research university known for its programs in astronomy, optical sciences, and medicine.
- Pima Community College: One of the largest multi-campus community colleges in the U.S., offering a wide variety of vocational and academic programs.
- Northern Arizona University (Tucson Campus): Offers undergraduate and graduate programs in education, business, and health sciences.
Major Landmarks
Pima County is known for its natural beauty and cultural landmarks, including Saguaro National Park, which protects the iconic Saguaro cactus and offers numerous hiking trails. Mission San Xavier del Bac, a historic Spanish Catholic mission, is one of the oldest intact European structures in Arizona. The Arizona-Sonora Desert Museum combines a zoo, botanical garden, and natural history museum, focusing on the flora and fauna of the Sonoran Desert. Sabino Canyon provides opportunities for outdoor recreation in the foothills of the Santa Catalina Mountains. The Pima Air & Space Museum showcases aircraft from various eras, and Tucson’s Presidio District preserves the city’s Spanish colonial heritage.
3. Yavapai County
County Facts
- Population: 236,209 (2020 Census)
- Area Codes: 928
- ZIP Codes: 85262-86339
- County Seat: Prescott
Geography and History
Yavapai County, located in central Arizona, covers 8,128 square miles and features a diverse landscape that ranges from desert in the southern part to forested mountains in the north, including the Bradshaw Mountains and Prescott National Forest. Established in 1864, Yavapai County was one of the original counties of the Arizona Territory. Prescott, the county seat, served as the territorial capital until 1867. The county has a rich mining history, particularly in gold, silver, and copper, which contributed to its early growth. Today, Yavapai County is known for its historical sites and outdoor recreation, attracting tourists and retirees.
Colleges and Universities
- Yavapai College: A community college offering associate degrees, vocational training, and transfer programs to four-year universities.
- Embry-Riddle Aeronautical University (Prescott Campus): A private university specializing in aviation, aerospace, and engineering programs.
- Prescott College: A private liberal arts college focused on environmental and social justice education.
Major Landmarks
Yavapai County is home to Montezuma Castle National Monument, a well-preserved cliff dwelling built by the Sinagua people. Prescott’s Courthouse Plaza is a historic area with a blend of old west architecture, while Whiskey Row reflects the county’s Wild West past. The Verde Canyon Railroad offers scenic train rides through beautiful red rock country. Outdoor enthusiasts flock to Watson Lake, known for its striking rock formations, and Sedona, famous for its red rock landscapes and spiritual significance. Jerome, a former mining town turned artist community, offers historic tours and art galleries.
4. Coconino County
County Facts
- Population: 145,101 (2020 Census)
- Area Codes: 928
- ZIP Codes: 86001-86052
- County Seat: Flagstaff
Geography and History
Coconino County, located in northern Arizona, is the second-largest county by area in the U.S., covering 18,661 square miles. Its geography is varied, featuring the Grand Canyon, the San Francisco Peaks, and the vast pine forests of the Coconino National Forest. The county was established in 1891 and named after the Coconino, a band of the Havasupai tribe. Flagstaff, the county seat, grew as a lumber and railroad town in the late 19th century. The county is home to several Native American tribes, including the Navajo and Hopi, and has a strong connection to the history of the American West. Today, tourism, education, and government are key economic drivers.
Colleges and Universities
- Northern Arizona University (NAU): A public university in Flagstaff offering a wide range of undergraduate and graduate programs, with a strong focus on forestry, education, and environmental sciences.
- Coconino Community College: Offers two-year degrees and technical programs, with an emphasis on transfer pathways to four-year institutions.
Major Landmarks
Coconino County is famous for Grand Canyon National Park, one of the world’s most iconic natural landmarks, attracting millions of visitors annually. Walnut Canyon National Monument preserves ancient cliff dwellings of the Sinagua people. Lowell Observatory in Flagstaff is a historic astronomical observatory where Pluto was discovered. The Wupatki National Monument features preserved Native American ruins. Outdoor activities are abundant in Oak Creek Canyon, a scenic gorge known for its hiking and camping opportunities. Sunset Crater Volcano National Monument offers views of a volcanic landscape, and Humphreys Peak, Arizona’s highest point, draws hikers and adventurers year-round.
5. Pinal County
County Facts
- Population: 425,264 (2020 Census)
- Area Codes: 520
- ZIP Codes: 85118-85245
- County Seat: Florence
Geography and History
Pinal County is located in south-central Arizona and covers 5,374 square miles. The county is characterized by desert landscapes, with mountains such as the Superstition Mountains to the north. Established in 1875, Pinal County’s economy was historically based on mining and agriculture, with cotton and copper being key industries. Florence, the county seat, is one of the oldest towns in Arizona and retains much of its historic charm. In recent years, Pinal County has experienced rapid population growth due to suburban development, particularly between Phoenix and Tucson.
Colleges and Universities
- Central Arizona College: A community college offering associate degrees and vocational training, with campuses throughout the county.
- Arizona State University Polytechnic Campus: Located in nearby Mesa but serves many Pinal County residents, offering degrees in technology, science, and engineering.
- Northern Arizona University (Casa Grande Campus): Provides programs in education, business, and health sciences.
Major Landmarks
Pinal County is home to Casa Grande Ruins National Monument, an ancient Hohokam site. The Superstition Mountains are legendary for their beauty and the fabled Lost Dutchman’s gold mine. Picacho Peak State Park offers hiking trails and historical reenactments of a Civil War battle fought in Arizona. Boyce Thompson Arboretum showcases desert plants from around the world, while Florence’s Historic District preserves the town’s Old West architecture. The Pinal Airpark, once a World War II training base, is now used for aircraft storage.
6. Mohave County
County Facts
- Population: 213,267 (2020 Census)
- Area Codes: 928
- ZIP Codes: 85360-86446
- County Seat: Kingman
Geography and History
Mohave County is located in the northwestern corner of Arizona, covering 13,461 square miles. The county is home to part of the Grand Canyon and Lake Mead, as well as desert landscapes and mountain ranges like the Black Mountains. Established in 1864, Mohave County played a significant role in the early mining and transportation industries, with mining camps and railroads bringing settlers to the area. Kingman, the county seat, grew as a transportation hub along Route 66. The county’s proximity to Nevada has also made it a destination for tourism and recreation.
Colleges and Universities
- Mohave Community College: A two-year institution offering associate degrees and technical certifications across multiple campuses.
- Northern Arizona University (Kingman Campus): Provides local access to higher education through partnership programs.
Major Landmarks
Mohave County features landmarks like Lake Havasu City, famous for the relocated London Bridge and a popular spot for water recreation. Oatman, a historic mining town, attracts visitors for its Wild West atmosphere and wild burros that roam the streets. Davis Dam on the Colorado River creates Lake Mohave, a key water recreation area. The county also encompasses parts of Grand Canyon-Parashant National Monument and the Hualapai Mountain Park, offering hiking and scenic views.
7. Navajo County
County Facts
- Population: 106,717 (2020 Census)
- Area Codes: 928
- ZIP Codes: 85901-86025
- County Seat: Holbrook
Geography and History
Navajo County is located in northeastern Arizona, covering 9,959 square miles of high desert and forested areas, including parts of the White Mountains. The county was established in 1895 and is named after the Navajo Nation, which occupies a significant portion of the area. Holbrook, the county seat, was an important stop along the Santa Fe Railway and Route 66. Historically, the county’s economy was based on ranching, logging, and mining, though tourism and outdoor recreation now play a larger role.
Colleges and Universities
- Northland Pioneer College: A community college offering associate degrees, vocational programs, and transfer opportunities to four-year universities.
Major Landmarks
Navajo County is home to Petrified Forest National Park, known for its ancient petrified wood and colorful badlands. Monument Valley, part of the Navajo Nation, is world-famous for its towering sandstone buttes. Snowflake is a historic Mormon settlement, while Winslow is a popular stop on historic Route 66. The Apache-Sitgreaves National Forests offer opportunities for camping, fishing, and hiking, especially in the cooler White Mountains.
8. Apache County
County Facts
- Population: 66,021 (2020 Census)
- Area Codes: 928
- ZIP Codes: 85920-86556
- County Seat: St. Johns
Geography and History
Apache County, located in northeastern Arizona, covers 11,218 square miles, stretching from the high deserts to the mountains of the Apache-Sitgreaves National Forests. Established in 1879, Apache County is named after the Apache people who inhabit the region. The county has a large Native American population, with the Navajo Nation and the White Mountain Apache Tribe making up a significant portion of the population. Historically, the area was influenced by both Native American and Spanish cultures, and its economy has traditionally been based on ranching and logging.
Colleges and Universities
- Northland Pioneer College: Serves residents with multiple campuses, offering two-year degrees and vocational training.
- Diné College: A tribal college serving Navajo students with associate and bachelor’s degree programs in areas like education and business.
Major Landmarks
Apache County’s most notable landmark is Canyon de Chelly National Monument, known for its dramatic cliffs and ancient cliff dwellings built by the Ancestral Puebloans. Four Corners Monument, where Arizona meets Utah, Colorado, and New Mexico, is a popular tourist destination. The Hubbell Trading Post is a historic site preserving the legacy of Native American trade. Window Rock, the capital of the Navajo Nation, features the Navajo Nation Museum and Council Chambers. The White Mountains offer numerous outdoor recreation opportunities, especially for winter sports.
9. Yuma County
County Facts
- Population: 203,881 (2020 Census)
- Area Codes: 928
- ZIP Codes: 85333-85369
- County Seat: Yuma
Geography and History
Yuma County, located in the southwestern corner of Arizona, covers 5,519 square miles, with the Colorado River forming its western boundary. The county’s desert landscape includes fertile agricultural lands irrigated by the river. Established in 1864, Yuma County’s history is tied to its location along the Gila and Colorado rivers, which made it a vital crossing point for settlers heading west. Yuma’s location near the border with Mexico also gave it strategic importance during times of conflict and trade.
Colleges and Universities
- Arizona Western College: A community college offering associate degrees, vocational training, and transfer programs to four-year institutions.
- Northern Arizona University (Yuma Campus): Provides local access to higher education through partnership programs, particularly in education and business.
Major Landmarks
Yuma County’s most famous landmark is the Yuma Territorial Prison State Historic Park, which offers a glimpse into the area’s law enforcement history during the Wild West era. The Colorado River State Historic Park preserves the history of riverboat travel and the U.S. Army’s Quartermaster Depot. Imperial Sand Dunes are popular for off-roading and desert recreation, while Lake Martinez is a favorite spot for boating and fishing. The Yuma Crossing National Heritage Area highlights the region’s historical significance as a crossing point along the Colorado River.
10. Cochise County
County Facts
- Population: 125,447 (2020 Census)
- Area Codes: 520
- ZIP Codes: 85602-85638
- County Seat: Bisbee
Geography and History
Cochise County is located in southeastern Arizona, covering 6,219 square miles. Its landscape includes high desert valleys and mountain ranges like the Dragoon Mountains. Established in 1881, Cochise County was named after the famous Apache chief Cochise. The county’s history is deeply intertwined with the Old West, particularly the silver mining town of Tombstone, which was the site of the famous gunfight at the O.K. Corral. The region’s economy initially depended on mining but has since diversified to include agriculture, tourism, and military installations, such as Fort Huachuca.
Colleges and Universities
- Cochise College: A community college offering associate degrees, vocational training, and transfer programs to four-year universities.
- University of Arizona (Sierra Vista Campus): Provides educational opportunities in fields such as business, education, and technology.
Major Landmarks
Cochise County’s most famous landmark is Tombstone, an Old West town preserved as a living history site, where visitors can see reenactments of the O.K. Corral gunfight. Bisbee, the county seat, is a former mining town known for its well-preserved Victorian architecture and artistic community. Fort Huachuca is a historic U.S. Army base still in operation today. The Chiricahua National Monument offers unique rock formations and scenic hiking trails, while the San Pedro Riparian National Conservation Area protects a rich ecosystem along the San Pedro River.