There was a combined $19 million of farms and rural land for sale in Saint Mary Parish recently on Land.com. The total size of all Saint Mary Parish land and rural real estate for sale was around 1,000 acres. Saint Mary Parish ranks 34th out of 64 counties in the Bayou State for the combined amount of land currently advertised for sale. Among cities in Saint Mary Parish with land for sale, Franklin had the most land for sale. Saint Mary Parish is one of the ten biggest counties in Louisiana (1,119 square miles). It's located in the Cajun Country Louisiana region of Louisiana.