Johnson County, Iowa facts for kids

Quick facts for kids Johnson County
U.S. county
Johnson County Courthouse
Seal
Location within the U.S. state of Iowa
Iowa's location within the U.S.
Country	United States
State	Iowa
Founded	December 21, 1837
Named for	Richard Mentor Johnson (1837–2020) Lulu Johnson (since 2020)
Seat	Iowa City
Largest city	Iowa City
Area
• Total	623 sq mi (1,610 km2)
• Land	614 sq mi (1,590 km2)
• Water	9.1 sq mi (24 km2)  1.5%
Population  (2020)
• Total	152,854
• Estimate  (2023)	157,528
• Density	250/sq mi (100/km2)
Time zone	UTC−6 (Central)
• Summer (DST)	UTC−5 (CDT)
Congressional district	1st

Johnson County is a place in Iowa, a state in the United States. In 2020, about 152,854 people lived here. This makes it the fourth-biggest county in Iowa by population. Its main city, called the county seat, is Iowa City. This city is also home to the famous University of Iowa. Johnson County is part of the larger Iowa City metropolitan area. It's also connected to the Cedar Rapids-Iowa City Corridor, which is a bigger area of cities.

History of Johnson County

Johnson County was created on December 21, 1837. This happened when the government of the Wisconsin Territory decided to form it. The land for the county used to be part of Dubuque County. At first, Johnson County didn't have its own local government. Officials from Cedar County helped manage things instead. The county was named after Richard Mentor Johnson, who was a Vice President of the United States.

Early Courthouses

The very first courthouse in Johnson County was a two-story log cabin. It was built in 1838 in a town called Napoleon. This town was about two miles south of where the current courthouse stands.

Later, Iowa City was chosen to be the new capital of the Iowa Territory. Because of this, Iowa City also became the county seat. The second courthouse for Johnson County was built in Iowa City in 1842. It cost $3,690 to build. This building was 56 feet long and 28 feet wide, with two stories.

Old Johnson County Courthouse, Iowa City, 1857-1899

A third courthouse was built in 1857. It was located in the courthouse square in Iowa City. This building was used until 1899. It had to be closed because cracks in its south wall made it unsafe. The building was made of brick with stone and wood decorations.

The Current Courthouse

The courthouse used today was designed by a company called Rush, Bowman and Rush. It cost $111,000 to build. The company Rowson and Son from Johnson County built it. The first stone of the building was placed in December 1899. The tall tower of the building looks like the spire of Trinity Church in Boston. The building was officially opened on June 8, 1901. There is also a jail next to the courthouse that is not used anymore.

Geography

Johnson County covers a total area of about 623 square miles (1,614 square kilometers). Most of this area, about 614 square miles (1,590 square kilometers), is land. The remaining 9.1 square miles (24 square kilometers) is water. This means about 1.5% of the county is covered by water.

Major Roads

Several important roads run through Johnson County:

• Interstate 80
• Interstate 380
• U.S. Highway 6
• U.S. Highway 218
• Iowa Highway 1
• Iowa Highway 22
• Iowa Highway 27

Neighboring Counties

Johnson County shares borders with several other counties:

• Linn County to the north
• Cedar County to the northeast
• Muscatine County and Louisa County to the southeast
• Washington County to the southwest
• Iowa County to the west
• Benton County to the northwest

Population Information

Population of Johnson County from US census data

2020 Census Details

The 2020 census counted 152,854 people living in Johnson County. This means there were about 250 people per square mile. Most people (93.62%) said they belonged to one race. About 69.93% were non-Hispanic White. Other groups included 8.40% Black, 6.67% Hispanic, 5.63% Asian, and smaller numbers of Native American and Pacific Islander people. About 9.13% were of another race or more than one race. There were 65,916 homes in the county, and 61,335 of them were lived in.

2010 Census Details

The 2010 census showed that 130,882 people lived in Johnson County. The population density was about 213 people per square mile. There were 55,967 homes, and 52,715 of them were occupied.

Towns and Communities

Johnson County has many different towns and communities.

Cities

Census-Designated Place

• Frytown

Other Unincorporated Communities

These are smaller communities that are not officially cities or towns:

Ghost Towns

• Midway

Townships

Johnson County is divided into several townships, which are smaller local government areas:

Population Ranking of Communities

The table below shows how many people lived in each city or community in Johnson County, based on the 2010 census.

† county seat

See also

In Spanish: Condado de Johnson (Iowa) para niños