Voter turnout in Cook County during the primaries was 30.84%, with 938,639 ballots cast. Among these, 795,427 Democratic, 137,286 Republican, 206 Green, and 5,720 nonpartisan primary ballots were cast. Turnout in the city of Chicago was 32.69%, and turnout in suburban Cook County was 29.05%.[3][4]
The general election saw 58.09% turnout, with 1,795,518 ballots cast. Turnout in Chicago was 60.67%, and turnout in suburban Cook County was 55.65%.[5][6] Turnout in Cook County exceeded the national average, which was 50.3%.[7] Turnout was considered high in the United States during the 2018 midterm elections, with it being the highest national midterm turnout since 1914.[8]
In the 2018 Cook County Assessor election, incumbent second-term assessor Joseph Berrios, a Democrat, lost his bid for reelection, being unseated in the Democratic primary by Fritz Kaegi, who went on to win the general election.
In the 2018 Cook County Clerk election, incumbent seventh-term clerk David Orr, a Democrat, did not seek reelection. Democrat Karen Yarbrough won the election to replace him.
By winning the election, Yarbrough became the first woman to ever hold the office of Cook County Clerk.[9]
Jan Kowalski McDonald was disqualified, and votes cast for her were not counted. However, due to ballot printing deadlines, her name was included on the ballot.[10]
Anticipating a potential wave election year for Democrats, President of the Cook County Board of Commissioners and Cook County Democratic Party Chairwoman Toni Preckwinkle made a focused effort to increase the Democrats' majority on the Cook County Board of Commissioners, focusing these efforts on three of the Board's four Republican-held seats. Preckwinkle-backed Democratic nominees ultimately succeeded in ousting Republican incumbents in the 14th and 15th districts, but fell roughly a mere 2,000 votes shy of unseating the 17th district's Republican incumbent.[11] Preckwinkle did not target the Republican-held 9th district seat, as the incumbent Republican, Peter N. Silvestri, was both popular and a political centrist and had a reputation for being a peacemaker on the Board at times when conflict arose between its members.[12]
Seven new members were elected,[13] and ten incumbents were reelected. Three incumbents did not seek reelection. Four incumbents lost reelection, with two being defeated in primaries and the other two losing their general elections.[2][1]
Two elections saw seats change party, in both instances seeing an incumbent Republican losing to a Democratic challenger, creating a net gain of two seats for Democrats and a net loss of two seats for Republicans. Nine races saw a Democrat unchallenged in the general election.[1]
In the 2018 Cook County Board of Review election, two seats, each Democratic-held, out of its three seats were up for election. Both incumbents won reelection, running unopposed in both their primary and general election races.
The Cook County Board of Review has its three seats rotate the length of terms. In a staggered fashion (in which no two seats have coinciding two-year terms), the seats rotate between two consecutive four-year terms and a two-year term.[14]
Incumbent second-term member Michael Cabonargi, a Democrat last reelected in 2016, was reelected, running unopposed in both the Democratic primary and general election. This election was to a four-year term.[14]
Incumbent fourth-term member Larry Rogers, Jr., a Democrat last reelected in 2014, was reelected, running unopposed in both the Democratic primary and general election. This election was to a four-year term.[14]
In the 2018 Metropolitan Water Reclamation District of Greater Chicago election, five of the nine seats on the Metropolitan Water Reclamation District of Greater Chicago board were up for election. Three were regularly scheduled elections, and two were special elections due to a vacancies.[2]
Three six-year term seats were up for a regularly-scheduled election. Since three six-year seats were up for election, voters could vote for up to three candidates,[15] and the top-three finishers would win.
Three of the incumbents for the three seats were seeking reelection, Kari Steele, Debra Shore, and Martin Durkan, all three Democrats. Steele and Shore won reelection to two of the seats, while Darkan lost renomination in the Democratic primary. Democrat Marcelino Garcia also won election was newly elected to the third seat.[16]
A special election was held to fill the seat vacated by Cynthia Santos following her 2016 appointment to the Illinois Pollution Control Board. The seat had been filled by interim appointee David Walsh up until the election.[16]
Three days before the candidate filing deadline, incumbent Water Reclamation District Board member Timothy Bradford's died, leaving his seat vacant. A special election was scheduled to fill his seat.[16] No candidates filed in time to be included on the primary ballots, but Cam Davis won the Democratic Party nomination and Geoffrey Cubbage won the Green Party nomination, each as write-in candidates.[16] Cam Davis won the general election.[16]
10 judgeships on the Circuit Court of Cook County were up for partisan elections due to vacancies. In each of these races, Democratic nominees went unchallenged in the general election.[1]Retention elections were also held for judgeships on the Circuit Court of Cook County. For the first time in three decades, a Circuit Court of Cook County judge (Matthew Coghlan) lost retention.[17]
29 subcircuit courts judgeships were also up for partisan elections due to vacancies.[1] Retention elections were also held for subcircuit courts judgeships.
Four ballot questions were included on ballots county-wide. One was included on primary ballots in March, while the other three were included on general election ballots in November.
A ballot question was referred by the Cook County Board of Commissioners to the voters of Cook County as to whether or not the county's voters advise the State of Illinois to legalize marijuana.[18] All 17 members of the Board of Commissioners had unanimously approved holding this ballot question.[18]
The question asked,
Shall the State of Illinois legalize the cultivation, manufacture, distribution, testing, and sale of marijuana and marijuana products for recreational use by adults 21 and older subject to state regulation, taxation and local ordinance?[18]
A ballot question was created by a successful initiative petition which asked Cook County voters whether to empower each city in Cook County to establish a law that allows workers to earn up to 40 hours a year of sick time.[19]
The ballot measure asked the question,
Shall your municipality match the Cook County earned sick time law which allows for workers to earn up to 40 hours (5 days) of sick time a year to take care of their own health or a family member’s health?[19]
A ballot question was created by a successful initiative petition which asked Cook County voters whether they believed that Illinois should strengthen penalties for the illegal trafficking of firearms and require all gun dealers to be certified by the State.[20]
The ballot measure asked the question,
Should the State of Illinois strengthen penalties for the illegal trafficking of firearms and require all gun dealers to be certified by the State?[20]
A ballot question was created by a successful initiative petition which asked Cook County voters whether to empower each city in Cook County to establish a $13 per hour minimum wage.[21]
The ballot measure asked the question,
Shall the minimum wage in your municipality match the $13 per hour Cook County minimum wage law for adults over the age of 18 by July 1, 2020, and be indexed to the consumer price index after that?[21]