Gretna is an unincorporated urban community in the Municipality of Rhineland within the Canadian province of Manitoba that held town status prior to January 1, 2015. Just north of the Canada- United States border on PTH 30, Gretna had a population of 541 in 2016. It is bordered by Pembina County, North Dakota. The nearest American community to Gretna is Neche, North Dakota.