Maricopa County, AZ
Maricopa County is located in south-central Arizona and encompasses an area of 9,224 mi². Within its boundaries lies five Indian reservations. It is the most populous county in the state, with 4,410,824 residents as of 2018. The county seat is located in Phoenix, which is also the state capital. Established February 14, 1781, the county was named after the Maricopa Indians.
Pima County, AZ
Established in 1894, Pima County has a population of 1,039,073, and covers an area of 9,189 mi² in southern Arizona. The county seat is located in Tucson, an area known for giant saguaro cactuses. The world’s largest privately funded air museum is located within its boundaries.
Pinal County, AZ
Pinal County is the third most populous county in Arizona, with a population of 447,138. The county seat is Florence, one of the oldest towns in the state. Downtown Florence is actually designated as a National Historic District. Pinal County was established in 1875.
Yavapai County, AZ
Named after the Yavapai Tribe, Yavapai County is located in central Arizona. With a population of 231,993, it is the fourth most populous county in the state. It encompasses an area of 8,128 mi² and was established in 1875. Prescott is the county seat. Nicknamed “everybody’s hometown,” Prescott is home to the Everybody’s Hometown Annual Festival each October.
Yuma County, AZ
Yuma County is located in southwestern Arizona and covers an area of 5,519 mi². Established 1874, it is the fifth most populous county in the state with an estimated population of 10,020. Yuma, the county seat, is known as the lettuce capital of the world. It's also the driest, sunniest, and least humid city in the United States. The area experiences an average of 4 inches of rain, 0 inches of snow and 308 days of sunshine per year.