2020 Cook County, Illinois elections
The primaries and general elections for Cook County races coincided with those for federal races (President, House, and Senate) and those for state elections. For the primaries, turnout was 33.54%, with 1,037,951 ballots cast. The ballots cast comprised 957,791 Democratic, 79,669 Republican, and 491 nonpartisan primary ballots. Turnout in the city of Chicago was 37.78%, while turnout in suburban Cook County was 29.42%. Turnout in the primaries was considered to be low for a presidential primary. The low turnout was attributed by many to the ongoing COVID-19 pandemic. The potentially suppressed turnout of election-day voting as a result of virus concerns was partially offset by high in-person early voting and mail-in ballot numbers. 339,000 people cast early votes, a record number, with Chicago seeing 172,000, and the rest of Cook County seeing 167,000 early votes, a record for each jurisdiction. The election also saw a record number of requests made for mail-in ballots, with both Chicago and the rest of Cook County seeing numbers of requests surpassing any previous election. In Chicago there were 118,000 such requests, with over 80,000 mail-in ballots ultimately being returned and counted. In suburban Cook County, 47,652 mail-in ballots were returned, setting a record. In Chicago, 45% of votes cast were either early votes or votes by mail. In suburban Cook County, 56% of votes cast were either early votes or votes by mail. The county's turnout was higher than the statewide turnout rate of 28.36%. For the general election, turnout was 72.20%, with 2,349,010 ballots cast. Turnout in the city of Chicago was 73.28%, while turnout in suburban Cook County was 71.18%. The county, as a whole, saw a turnout that was slightly below the statewide turnout rate of 72.92%. The incumbent fifth-term clerk of the Circuit Court of Cook County, Dorothy Brown, announced in 2019 that she would not run for re-election. Brown had been the subject of a federal corruption investigation when she made the announcement. Democrat Iris Martinez was elected to succeed her. The last Republican to hold this office was Brown's immediate predecessor Aurelia Pucinski, who, while elected a Democrat in each of her elections to the office, had switched parties in her final term. All four candidates in the Democratic Party primary for the office pledged to modernize the office and to address corruption. Candidates
The following candidates ran for the Democratic Party nomination for Clerk of the Circuit Court:
Endorsements
Polls
Results
Candidates The following candidates ran for the Republican party nomination for Clerk of the Circuit Court: 
Write-in candidates
Results
Endorsements
Results Incumbent Cook County state's attorney Kim Foxx won reelection to a second term. Foxx defeated three opponents in the Democratic primary and Republican Pat O'Brien in the general election. Only Democrats have held this office ever since Richard A. Devine unseated Republican Jack O'Malley in 1996. Incumbent Kim Foxx faced three opponents in the, two former Assistant State's Attorneys, Bill Conway and Donna More, and former Chicago alderman Bob Fioretti. The money spent in the Democratic primary made this the most expensive State's Attorney election in Cook County to date. Conway raised $11.9 million in campaign funds, most of which was from his father William E. Conway's cumulative donations of $10.5 million. Foxx raised $2.8 million, and her biggest donors include Fred Eychaner and the political action committee of SEIU Illinois. More raised $406,000 and Fioretti raised $20,000. Candidates
The following candidates ran for the Democratic Party nomination for State's Attorney:
Endorsements
Polls
Results Pat O'Brien defeated Christopher Pfannkuche. Pfannkuche had been the Republican nominee for State's Attorney in 2016. Candidates
The following candidates ran for the Republican party nomination for State's Attorney: 
Write-in candidates
Endorsements
Results
Polls
Endorsements
Results In the 2020 Cook County Board of Review election, one seat, Republican-held, out of its three seats is up for election. Incumbent Dan Patlak is seeking reelection. 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. Incumbent second-term Cook County Board of Review Commissioner for the 1st district, Dan Patlak, a third-term Republican last reelected in 2016, was unseated by Democrat Tammy Wendt. This election was to a two-year term. Candidates The following candidates ran for the Democratic Party nomination:
Endorsements
Results
Candidates The following candidates ran for the Republican party nomination: 
Results
Endorsements
Results Three of the nine seats on the Metropolitan Water Reclamation District of Greater Chicago board are up for election in 2020. Each winning candidate will serve a six-year term on the board. All candidates will appear together on the ballot, and voters can vote for up to three candidates (in both the primary and the general). All three incumbents were Democrats. Incumbents Kimberly Neely Dubuclet and Cam Davis won reelection, while Frank Avila lost renomination. Democrat Eira L. Corral also won election. Candidates The following candidates are running for the Democratic Party nomination:





The following candidates were removed from the ballot:
Results No candidates were included on the ballot in the Republican primary. While two official write-in candidates did run, neither received a sufficient share of the vote for them to win nomination. Write-in candidates

Results The Green Party nominated Troy Hernandez, Tammie Vinson, and Rachel Wales.
Endorsements
Results Partisan elections was held to fill 13 judgeships in the Circuit Court of Cook County and 21 judgeships in subcircuits of the court. There were Democratic Party candidates for all 34 elections, whereas the Republican primary had been canceled for all but two vacancies. Retention elections were also held for judgeships on these courts.
Cook County Board of Review
The Cook County, Illinois general election was held on November 3, 2020.