Old Jefferson is a census-designated place (CDP) in East Baton Rouge Parish.
The population was 5,631 at the 2000 census. It is part of the Baton Rouge Metropolitan Statistical Area.
Old Jefferson is served by East Baton Rouge Parish Public Schools. The CDP is zoned to Jefferson Terrace Elementary School, Woodlawn Middle School, and Woodlawn High School. The district provides transportation to the following private Catholic schools: Most Blessed Sacrament School (PK-8) and St. Michael the Archangel High School (9-12).