Zachary was named for a local farmer who owned the land that became the present city of Zachary. The first post office opened in 1885, and it was incorporated as a city in 1889. The first census in 1914 reported just 419 residents. By 1980, there were 7,525 residents, in 2000 there were 11,275 residents. Zachary was the first city in Louisiana to elect a Republican as mayor in 20th-century Louisiana. Jack Louis Breaux, Sr., served as a part-time mayor from 1966–1978, and a full-time mayor under a home-rule charter from 1978 until his death of a brain tumor on January 26, 1980.