Louisville, actually would have been Lewisville named for the Lewis family that was prominent there prior to the war and as Terry said it was on the major military road from Monroe-W. Monroe (Cottonport then) to Natchitoches.

As for Ike Gans, Ike really wasn't a carpetbagger as claimed in some earlier histories but a Jewish merchant connected to the Bernstein family of Montgomery and Winnfield who ended up opening a store in Lewisville and gaining the post office about the time the war ended. The place then became Gansville named for Ike.