Organized by Coalition for Humane Immigrant Rights, or CHIRLA, the event was attended by community members who said potential mass deportations would cause pain, suffering and chaos.
In January "we're going to have a lot of fearful things that the Trump administration said they were going to do," said Katia Garcia, a CHIRLA spokesperson. "We're starting to protest. This vigil is for us to actually send a message that we need to keep families together."
Trump has said he plans to begin his deportation efforts on the first day of his presidency. He frequently attacked illegal immigration during his campaign, linking a record spike in unauthorized border crossings to issues ranging from drug trafficking to high housing prices.
There are an estimated 11 million people in the country illegally. Questions remain about how people would be identified and where they would be detained.
On Tuesday, the L.A. City Council approved a so-called "sanctuary city" ordinance that bars city resources from being used for immigration enforcement and city departments from sharing information on people without legal status with federal immigration authorities.
Councilmembers voted unanimously on the measure, joining more than a dozen cities across the United States with similar provisions. Sanctuary cities or states are not legal terms but have come to symbolize a pledge to protect and support immigrant communities and decline to voluntarily supply information to immigration enforcement officials. Advocates say they are havens for immigrants to feel safe and be able to report crime without fear of deportation.
The Associated Press contributed to this report.