Zachary is a city in East Baton Rouge Parish, Louisiana, United States. It lies 16 miles (26 km) north of the city of Baton Rouge, and had a population of 14,960 at the 2010 census, up from 11,275 in 2000. At the 2020 census, Zachary's population increased to 19,316.

East Baton Rouge Parish is the most populous parish in the U.S. state of Louisiana. Its population was 456,781 at the 2020 census. The parish seat is Baton Rouge, Louisiana's state capital. East Baton Rouge Parish is located within the Greater Baton Rouge area.