There were also some pro-President Trump counter protesters.
The demonstrators described the facility as having inhumane, prison like conditions. But some had other concerns as well.
"We are here to ask and demand the reunification of families in an orderly way," said Tessie Borden, communications manager of the Coalition for Humane Immigrant Rights (CHIRLA).
There was no violence and no arrests at Friday's protest as law enforcement kept the two groups separated.
The facility, which is located in San Bernardino County, houses nearly 2,000 immigrant detainees.