Marrero is a census-designated place (CDP) in Jefferson Parish, Louisiana, United States. Marrero is on the south side (referred to as the "West Bank") of the Mississippi River, within the New Orleans–Metairie–Kenner Metropolitan Statistical Area. The population was 33,141 at the 2010 census.
Marrero was named in honor of the Louisiana politician and founder of Marrero Land Company, Louis H. Marrero. The area was originally referred to and shown on maps as "Amesville", after the Boston businessman Oakes Ames, who purchased much of the land following the Civil War. In February 1916, the U.S. Postmaster officially changed the name of the Post Office to "Marrero".
Louis Herman Marrero was born in Adams County, Mississippi, on July 17, 1847. When he was a child his family moved to St. Bernard Parish, Louisiana. During his school years at Jackson, Louisiana, the Civil War began, and Marrero joined Captain Scott's Command, later known as the 25th Louisiana Regiment.
Marrero is located west of the Intracoastal Canal on the Mississippi River, at coordinates 29°53′10″N 90°6′36″W (29.886017, -90.109930). It is bordered to the east by Harvey, to the west by Westwego, and to the north, across the Mississippi, by New Orleans.
According to the United States Census Bureau, the Marrero CDP has a total area of 8.6 square miles (22.3 km2), of which 8.0 sq mi (20.6 km2) are land and 0.66 sq mi (1.7 km2), or 7.66%, are water.
As of the census of 2010, there were 33,141 people, 12,218 households, and 8,629 families residing in the CDP. There were 13,212 housing units, of which 994, or 7.5%, were vacant.