Gretna is located in Sarpy County 10 miles SW of Omaha along Highway 6 near Memphis Lake State Recreation Area and Two Lakes State Recreation Area.
Gretna is part of the Omaha, Nebraska-Iowa metro area.
The Burlington Railroad started building a line between Omaha and Ashland and a town started to take shape. The new town, located on "common school lands," was given the name "Gretna" for "Gretna Green" in Dumfriesshire, Scotland, the home of some of the Scottish residents. A deed was purchased by the Lincoln Land Company in April, with a plat surveyed and recorded on August 9, 1886.