The north and northwest areas of the county, though historically rural and exurban, have experienced rapid suburbanization in the past three decades, while the lakefront communities of Waukegan, North Chicago, and Zion are postindustrial areas that have majority-minority populations.

The expansive Naval Station Great Lakes is located in the city of North Chicago.

One Wetland of International Importance is primarily located in the county, Chiwaukee Prairie Illinois Beach Lake Plain, which encompasses Illinois Beach State Park and some of the lakeside lands of the Lake County Forest Preserve District.

Lake County's first courthouse was built on part of that land in 1844 and the remainder was sold to pay for the $4,000 construction cost.

When fire damaged the courthouse on October 19, 1875, the county records were saved because they were in the adjacent building.

This courthouse, however, was demolished in 1967 to make room for a new high-rise administration building, which was completed with the addition of the jail in 1969 and courts in 1970.

Shortly thereafter, the Lake County Board commissioned the construction of a multi-faceted justice facility and ground was broken in 1986 for the Robert H. Babcox Justice Center, named in memory of Sheriff Babcox, who served as Lake County Sheriff from 1982 to 1988.

The justice center, which houses the county jail, work release program, sheriff's administration offices and three courtrooms, was finished in 1989 at a cost of $29.6 million.

45/Old Half Day Road, was one of the oldest structures in Lake County until it was demolished in 2007 to make way for retail space, condominiums, and a retention pond.

[4] A long north–south string of the preserves in Lake County, including Half Day Woods, Old School Forest Preserve, Independence Grove, and Van Patten Woods, form the Des Plaines River Greenway, which contains the Des Plaines River Trail, a popular place for walking, running, and biking.

While both systems' can be seen on official road maps, only the County Route designations have been indicated with highway markers on traffic signals or dedicated poles.

[27] Racial Makeup of Lake County (2023)[28] Racial Makeup of Lake County excluding Hispanics from Racial Categories (2023)[28]NH=Non-Hispanic Racial Makeup of Hispanics in Lake County (2023)[28] According to 2023 US Census Bureau American Community Survey one-year estimates (which is conducted annually for cities over 65,000 via sampling), the population of Lake County, Illinois was 60.2% White (55.6% Non-Hispanic White and 4.6% Hispanic White), 6.1% Black or African American, 8.8% Asian, 0.9% Native American and Alaskan Native, 0.1% Pacific Islander, 10.9% Some Other Race, and 12.9% from two or more races.

If treated as a separate category, Hispanics are the largest minority group in Lake County, Illinois[28] surpassing the Black population from the 1990 Census onward.

Each of these elected officers serves a term of four years and oversees a different part of county government.

As a historic Yankee settlement, Lake County was initially a stronghold of the Free Soil Party.

In the 1848 presidential election, it was Free Soil nominee and former president Martin van Buren’s strongest county, giving him over 58 percent of the vote.

This tradition was only broken in 1912, when the GOP was mortally divided and Lake County voted for Progressive Party nominee and former president Theodore Roosevelt over conservative incumbent William Howard Taft.

In 1964 the Republican Party nominated Barry Goldwater, whose hostility to the Yankee establishment and strongly conservative platform were sufficient to leave many traditional Republicans to stay home or even to vote for Lyndon Johnson, who narrowly became the first Democrat to win an absolute majority in the county since James K. Polk in 1844, and the first to win it at all since Pierce in 1852.

Between 1968 and 1988, however, Lake County became powerfully Republican once more, with no Democrat cracking forty percent of the vote.

After narrowly voting for George W. Bush twice, in 2008 it swung over dramatically to support Democrat Barack Obama, who carried it by almost 20 points.