Voters in Philadelphia are determining who will likely lead the nation's sixth-largest city in a crowded field of Democratic candidates on Tuesday, as the city faces upticks in gun violence and quality-of-life issues that make people feel unsafe.

Five front-runner candidates — including former city council members, former city officials and a grocery store franchiser — have sought to differentiate themselves in a tight contest.

The Philadelphia race serves as the latest barometer of how residents of some of the nation’s largest cities hope to emerge from the pandemic, which heightened concerns about crime, poverty and inequality. The results have sometimes been tumultuous in other parts of the country, leading to the defeat of the incumbent mayor of Chicago in February and the ouster of San Francisco’s district attorney last year.

Philadelphia voters will choose between front-runner candidates including former council members Allan Domb, Helen Gym and Cherelle Parker; former city controller Rebecca Rhynhart; and political outsider and grocer Jeff Brown. They are vying to replace Democratic Mayor Jim Kenney, who is term-limited.

Only one Republican, former city council member David Oh, is running. He and the Democratic nominee will face each other in the Nov. 7 general election. Because Philadelphia is heavily Democratic, it is likely that whoever wins the primary will become the next mayor.

The candidates have pledged to tackle the city's violence and crime, and address the rampant quality-of-life issues, but how they plan to get there varies. The candidate who is able to muster their base and appeal to the widest cross-section of voters will ultimately tip the scales in a tight contest.

Voters on Tuesday will also elect seven out of more than 30 total Democratic and Republican candidates for city council-at-large seats and three contested district seats.

To the west, voters in Allegheny County, which encompasses the state's second largest city of Pittsburgh, will choose among six Democratic candidates vying to replace the county's top official, who is term-limited. The winner will face a lone Republican contender in the November general election. Unlike in the Philadelphia mayor's race, the primary winner will not necessarily be the person most likely to fill the county executive's seat.