Boston City Council preliminary election day is today. Here’s what to know before you vote.

The city’s preliminary election is slated for Sept. 12, with the general election to follow on Nov. 7.

Here is everything you need to know to vote in this year’s municipal elections in Boston.Craig F. Walker/Globe Staff

Boston’s preliminary election day is Tuesday, and some of the City Council candidates up for reelection made headlines this summer.

Eligible Bostonians can cast their ballots Sept. 12 in the city’s preliminary election, which will narrow the list of candidates running to be district councilors down to two in each District 3, 5, 6, and 7. These candidates will then go on to compete in the general election on Nov. 7.

Several incumbents are facing new challengers, including those caught in controversies in recent months.

Up for reelection in District 6, Kendra Lara has been under fire after allegedly driving twice the speed limit with a revoked driver’s license when she reportedly crashed an unregistered and uninsured car into a Jamaica Plain home earlier this summer. Lara is facing nine criminal charges connected to the crash, and has pleaded not guilty.

Meanwhile, District 5 Councilor Ricardo Arroyo has been embroiled in several controversies, including an ethics violation and years-old sexual assault allegations that came up last year, which he has denied and never been charged for.

After a chaotic City Council term, here is everything you need to know about voting in this year’s municipal elections in Boston.

Key Dates:

Sept. 12: Preliminary election day. Voters have from 7 a.m. to 8 p.m. to cast their votes in races for Districts 3, 5, 6, and 7. (Elections for other districts and at-large councilors have drawn fewer contenders and will take place only in November.)

Oct. 28: The deadline to register to vote in the general election is 5 p.m.

Oct. 31: The deadline to request your vote-by-mail ballot for the general election is 5 p.m.

Nov. 7: General election day. Voters have from 7 a.m. to 8 p.m. to cast their votes for district and at-large city councilors.

Where do I vote?

Bostonians can find their polling location by inputting their address on the secretary of state’s website.

How do I vote by mail?

If you are a registered voter, you can submit a vote-by-mail application through the Massachusetts Mail-in Ballot Application System or apply by email or fax. If you are not a registered voter, you can register to vote and request a mail-in ballot at the same time.

The deadline to request your vote-by-mail ballot was on Sept. 5 for the preliminary municipal election on Sept. 12. The deadline to request your vote-by-mail ballot is 5 p.m. on Oct. 31 for the general election on Nov. 7.

For a ballot to be counted, it must reach the Boston Election office by the close of polls on Election Day. For the preliminary election, this is 8 p.m. on Sept. 12. For the general election, this is 8 p.m. on Nov. 7. Mailed ballots may be tracked through the state’s website.

Ballots may also be placed in designated drop boxes by 8 p.m. on Sept. 12. They may not be dropped off at polling locations. The list of drop box locations has not been finalized but will be published on the city’s website upon completion.

How do I find my district?

After a lengthy and contentious once-in-a-decade redistricting process, including a legal battle, the City Council in May approved a new council district map with changes to some district boundaries. Most district boundaries remain the same, but there are significant shifts in Dorchester, Mattapan, and the South End to balance the population based on the decennial census, affecting Districts 3 and 4.

This map indicates which areas belong to which City Council districts.

Who’s on the ballot?

The preliminary election will narrow down the district races to two candidates in districts with three or more people running.

Here are the candidates on the ballot in September’s preliminary election. The top two vote-getters in each race will move on to the November ballot:

District 3: Frank Baker is the sitting district councilor and is not running for reelection. John FitzGerald, Jennifer Johnson, Barry Lawton, Matthew Patton, Joel Richards, Ann Walsh, and Rosalind Wornum are all running. Read more about the District 3 race here.

District 5: Ricardo Arroyo is running as an incumbent. Enrique José Pepén, Jose Ruiz, and Jean-Claude Sanon are also running. Read more about the District 5 race here.

District 6: Kendra Lara is running as an incumbent. William King and Benjamin Weber are also running. Read more about the District 6 race here.

District 7: Tania Fernandes Anderson is running as an incumbent. Althea Garrison, Jerome King, Roy Owens, and Padma Scott are also running. Read more about the District 7 race here.

Here are the candidates going straight to the ballot in November’s general election:

District 1: Gabriela Coletta is running unopposed as an incumbent.

District 2: Ed Flynn is running unopposed as an incumbent.

District 4: Brian Worrell is running unopposed as an incumbent.

District 8: Kenzie Bok recently stepped down as District 8′s councilor to assume a new role leading the Boston Housing Authority, and Sharon Durkan won her seat in a special election that took place on July 25. Durkan must compete again in November to earn a full term in the seat. She is competing against Montez Haywood.

District 9: Liz Breadon is running as an incumbent. Jacob deBlecourt is also running.

Councilor at large: Voters will decide who secures the four city councilor at large seats in the general election on Nov. 7. Ruthzee Louijeune, Julia Mejia, and Erin Murphy are all running as incumbent candidates (Michael Flaherty will not seek reelection). Also running are Clifton Braithwaite, Bridget Nee-Walsh, Shawn Nelson, Henry Santana, and Catherine Vitale.

District races to watch

Boston City Council has been rocked by controversy involving a few different councilors recently, and it remains to be seen whether Bostonians will be swayed enough to vote for change.

Arroyo, who represents District 5, paid a $3,000 ethics fine in June after representing his brother, a former city Cabinet chief, in a sexual harassment lawsuit while also serving as a councilor. Last year, in his bid to be Suffolk district attorney, Arroyo also faced years-old allegations of sexual assault. He has denied those allegations and never been charged. Arroyo’s name also appeared in bombshell government reports showing that former US attorney Rachael Rollins used her position to try to influence his election for district attorney.

Arroyo’s reelection is challenged by three candidates: Enrique José Pepén, a Roslindale resident who served as executive director of the city’s neighborhood services; Jose Ruiz, a Hyde Park resident and chief of public safety for the Boston Public Health Commission, and Jean-Claude Sanon a Mattapan resident who has run for the office before.

Pepén recently issued an apology after facing questions about campaign law violations including $11,000 in campaign contributions for June, which goes against state law governing paid municipal employees’ political activity.

Meanwhile, Lara, who represents District 6, is running to continue serving after a controversial first term in office.

A self-proclaimed socialist known for her progressivism, Lara currently faces criminal charges for allegedly driving with a revoked license and crashing an unregistered, uninsured car into a Jamaica Plain home at more than twice the speed limit; she also received backlash over a seemingly illegal attempt to override Mayor Michelle Wu’s budget items and an antisemitic tweet.

Her opponents are William King, an IT director who lives in West Roxbury, and Benjamin Weber, a workers’ rights lawyer who lives in Jamaica Plain.

Frank Baker, a Dorchester native who grew up attending St. Margaret’s Parish, announced in April that he is not running for reelection after holding the District 3 seat since 2011. Baker’s work focused on constituent services, and although he is a registered Democrat, he is known as one of the last of a fleeting type of Boston politician: a conservative traditionalist who focuses on tending to parks, playgrounds, streets, and schools.

Now that he will no longer be on the Council, a number of candidates are seeking his seat:

• John FitzGerald, a resident of Adams Village in Dorchester and deputy director of operations for real estate for the Boston Planning and Development Agency;
• Jennifer Johnson, a resident of Meetinghouse Village in Dorchester and former president of the Meetinghouse Hill Civic Association;
• Barry Lawton, a resident of Upham’s Corner in Dorchester and former aide at City Hall and the State House who has run for the Fifth Suffolk House seat multiple times;
• Matthew Patton, a resident of Savin Hill in Dorchester and labor attorney at Lichten & Liss-Riordan;
• Joel Richards, a resident of Parkman Place in Dorchester and teacher at the Blackstone Elementary School who is newly a part of District 3 due to the city’s new redistricting map;
• Ann Walsh, a resident of Dorchester who previously served as former city councilor John Connolly’s chief of staff and co-founded an education nonprofit with him; and
• Rosalind Wornum a housing activist who lives in the Ashmont area.