Drivers stepped out of their cars on Octavia Street to watch the crowd of protesters pass by on Market Street.
RELATED: Families Belong Together demonstrations protesting family separation take place in cities across America
Joan Baez and representatives from several organizations, including Mujeres Unidas y Activas, CA Domestic Workers and Causa Justa, are scheduled to speak at the at the San Francisco rally.
Event organizers include Families Belong Together San Francisco, Women's March San Francisco and Indivisible SF.
Another event in Oakland will take place from 10:30 a.m. to 12:30 p.m. at Lakeside Park, near Staten and Bellevue avenues. The family-friendly rally will feature children's activities and youth speakers.
Click here for a complete list of events.
More than 2,000 children have been separated from their parents in recent weeks and placed in government-contracted shelters. President Donald Trump last week issued an executive order to stop the separation of families and said parents and children will instead be detained together.
PHOTOS: Families Belong Together demonstrators denounce family separation around America
For more on the Crisis at the Border, visit this page.
The Associated Press and Bay City News contributed to this report