As tens of thousands of delegates and guests arrive for the Democratic National Convention, they will encounter a sight familiar to Chicagoans but startling to most out-of-towners: clusters of migrants from Central and South America, congregating in parks, near highway overpasses and in the Loop, where women and small children on sidewalks sell candy or plead for money with cardboard signs.

Two years after a surge of migrants began arriving at the nation’s southern border, the crisis continues to play out on Chicago’s streets. Families who fled political corruption, violence and poverty in Venezuela and other countries have become a ubiquitous presence in many of Chicago’s neighborhoods, especially in the downtown area, close to the convention’s main site, the United Center.

The administration of Mayor Brandon Johnson of Chicago has said that it will not try to compel migrants to move out of sight during the convention. That leaves one of the country’s most difficult policy issues on display in stark human terms for this week’s visitors, reminding convention guests of a potential liability — the migrant crossings during the Biden administration — going into the November presidential election.

Around downtown, migrants are not sleeping overnight on the sidewalks, they say, and some are staying in hotels that have been converted into shelters. A large number appear to be living in apartments that they obtained with government housing assistance, commuting downtown each day to sell candy and earn cash.

Very few have English skills or official work authorization, leaving them in a limbo of illegal street vending that is often ignored by police officers.

They have often been viewed with suspicion by some neighborhood residents, deepening broader tensions in Chicago — often infused with conflicts on race and class — over the question of how much city resources should be devoted to the migrants.