The city of Gretna is the parish seat of Jefferson Parish, in the US state of Louisiana. Gretna is on the west bank of the Mississippi River, just east and across the river from uptown New Orleans. It is part of the New Orleans–Metairie–Kenner Metropolitan Statistical Area. The population was 17,736 at the 2010 census.
Gretna was settled in 1836, originally as Mechanicsham, growing with a station on the Mississippi River for the Missouri Pacific Railroad, Texas and Pacific Railway, and Southern Pacific Railroad, with a ferry across the River to New Orleans. The famous spice-maker Zatarain's was founded here in 1889. Gretna was incorporated in 1913, absorbing the section of McDonogh within the Jefferson Parish boundaries. In the 1940 census, Gretna had a population of 10,879.
The City of Gretna received considerable press coverage when, in the aftermath of Hurricane Katrina (late August 2005), people who attempted to escape from New Orleans by walking over the Crescent City Connection bridge over the Mississippi River were turned back at gunpoint by City of Gretna Police, along with Crescent City Connection Police and Jefferson Parish Sheriff's deputies, who set up a roadblock on the bridge in the days following the hurricane. According to eyewitnesses, some of these officers threatened to shoot New Orleans residents and tourists as they attempted to cross into Gretna on foot.