This is a blowup of the Carter County region of the main map below. Much of the resolution is lost
in the blowup, but the Scioto River is the verticle line in the upper center of this image.
The Big Sandy is in the verticle line in the center of the lower center of the image,
with the Little Sandy River just to its left.
The unlabeled inch long line between the Little Sandy River and the junction of the Scioto and Ohio Rivers is Tygarts Creek.
The faint line to the left of Tygarts Creek is the old trail from central Ohio which crossed
the Ohio River to the west of the mouth of the Scioto River and proceeded from there into central Kentucky.
I have been unable to find a large scale version of the full map, this one is almost unusable.
I understand this is a very informative map when viewed in its legible form.