The Sulphur River begins at the confluence of its north and south forks forming (following earlier meanders) the northern and southern boundaries of, and meeting at the eastern end of, Delta County (Texas).

The river provides most of the water for Wright Patman Lake, on the border between Bowie and Cass counties.

Below Wright Patman Dam, the river continues its generally eastward flow to the Arkansas state line.

The flow is slow, and the river is murky, largely due to channelization upstream.

Wright Patman Lake provides additional opportunities for camping, boating, swimming, and fishing.