 Saint Helena meridian

Saint Helena meridian () begins at the initial point of the Washington meridian, in latitude 31° north, and longitude 91° 09′ 15″ west of Greenwich, passing one mile east of Baton Rouge, extends south to the Mississippi River, and governs the surveys in the Greensburg and southeastern districts of Louisiana, east of the Mississippi River.The Saint Helena meridian has a common initial point with the Washington meridian, which runs north from the initial point and governs cadastral surveys in southwestern Mississippi.