[3] The development of the county was greatly furthered by the arrival of the Chicago Branch of the Illinois Central Railroad, and even more by the establishment of the land-grant university.

The northern part of the county experienced an economic and demographic setback with the closing of Chanute Air Force Base in the 1990s.

Lobes of ice from what is now Lake Michigan crossed the county, creating a deep pile of glacial soil, up to 300 feet thick, topped by numerous moraines forming small, flat watersheds with no outlets.

The Embarras River, on the other hand, drains the south-central portion of Champaign–Urbana, originating in southeastern Champaign and flowing through the experimental fields on the southern part of the campus of the University of Illinois.

The northeast corner of Champaign, the central portion of the University campus, and the northern part of Urbana are drained by the Boneyard Creek, which flows into the Saline Branch, a tributary of the Vermilion and Wabash rivers.

Amtrak, Greyhound, and Peoria Charter operate intercity buses from Champaign–Urbana to Chicago, St. Louis, Indianapolis, and other destinations.

[13][14] The Champaign–Urbana Mass Transit District operates public city buses in Champaign, Urbana, and Savoy.

[16] In August 2018, the Champaign County Board voted to approve solar farms on certain agricultural properties.

In order to make the solar farms, developers must obtain a special permit from the county board first.

[26] The Champaign County Economic Development Corporation (CHCEDC) produced a 2009 County Demographic Profile which includes information on the population, labor, housing, cost of living, education, taxes, retail sales, transportation, quality of life, utilities.

[46] Supported by the University of Illinois, through backings such as the Research Park, and Champaign County leaders, the area has shown even more growth in Information Technology, Micro/Nanotechnology, Bio-Imaging, Healthcare, Logistics, Distribution, and Agribusiness in recent years.

[47] As of 2023, the top 15 employers in the county are the University of Illinois, Carle Foundation Hospital, Champaign Schools Unit 4, Kraft Heinz, OSF Healthcare, Parkland College, Kirby Foods, Christie Clinic, Champaign County Government, Urbana School District #116, FedEx, Plastipak, Rantoul Foods, Busey Bank, and SuperValu.

[49] Like most of central Illinois, Champaign County was powerfully Republican between the Civil War and the latter portion of the 20th century.

Since 2004, it has given a majority of the vote to Democratic candidates due to the county's liberalism, as home to the University of Illinois Urbana-Champaign.