Map of Adams County, Illinois

Adams County is the westernmost county in the U.S. state of Illinois. As of the 2020 census, the population was 65,737. Its county seat is Quincy. Adams County is part of the Quincy, IL–MO Micropolitan Statistical Area.

Adams County overview:
Name:	Adams County
FIPS code:	17-001
State:	Illinois
Founded:	1825
Named for:	John Quincy Adams
Seat:	Quincy
Largest city:	Quincy
Total Area:	871 sq mi (2,260 km²)
Land Area:	855 sq mi (2,210 km²)
Total Population:	65,737
Population Density:	75/sq mi (29/km²)
Time zone:	UTC−6 (Central)
Summer Time Zone (DST):	UTC−5 (CDT)
Website:	www.co.adams.il.us

Adams County location map. Where is Adams County?

Adams County location on the U.S. Map. Where is Adams County. — Location of Adams County in the the United States.

Adams County location on the Illinois map. Where is Adams County. — Location of Adams County in Illinois.

History

Adams County was formed in 1825 out of Pike County. Its name is in honor of the sixth President of the United States, John Quincy Adams.

When it was created, Hancock County was temporarily attached to Adams until it could organize a county government.
Adams County reduced to its current borders in 1829.

Adams County Road Map

Adams CountyStreet Map. — Street map of Adams County, Illinois. Source: OpenStreetMap (OSM)

Adams CountyMap — Adams Countypolitical map.

Geography

According to the U.S. Census Bureau, the county has a total area of 871 square miles (2,260 km), of which 855 square miles (2,210 km) is land and 16 square miles (41 km) (1.9%) is water.

Adjacent counties

Hancock County – north
Brown County – east
Schuyler County – east
Pike County – south
Marion County, Missouri – west
Lewis County, Missouri – west

Public transit

Quincy Transit Lines
Quincy station
Burlington Trailways
List of intercity bus stops in Illinois

Major highways

Interstate 172
US Route 24
US Route 36
Illinois Route 57
Illinois Route 61
Illinois Route 94
Illinois Route 96
Illinois Route 104
Illinois Route 336

National protected area

Great River National Wildlife Refuge (part)

Climate and weather

In recent years, average temperatures in the county seat of Quincy have ranged from a low of 16 °F (−9 °C) in January to a high of 88 °F (31 °C) in July, although a record low of −21 °F (−29 °C) was recorded in January 1979 and a record high of 105 °F (41 °C) was recorded in July 2005. Average monthly precipitation ranged from 1.36 inches (35 mm) in January to 4.61 inches (117 mm) in May.