The Big Sandy River is a tributary of the Ohio River, approximately 27 mi (43), in western West Virginia and eastern Kentucky in the United States. The river forms part of the boundary between the two states along its entire course.
The river is navigable and carries commercial shipping, primarily coal mined in the nearby region.
The name of the river comes from the presence of extensive sand bars. The Native American names for the river included Tatteroi, Chatteroi, and Chatterwha which had similar meaning to the English name. It was known to the Lenape as Sikeacepe, meaning "Salt River", from the presence of salt licks on the river (see: Licking River).