South Salt (Irish: An Léim Theas) is a barony in County Kildare, Ireland.

South Salt derives its name from the Latin name of Leixlip: Saltus salmonis (literally "salmon leap"; the English name is derived from Old Norse Lax-hlaup).

This makes Salt one of very few Irish placenames derived directly from Latin.

South Salt barony is located in northeast County Kildare, south of the Liffey, bordering on County Dublin.

This article related to the geography of County Kildare, Ireland is a stub.