I fish a lake impounded in 1945. I would love to have a structure map. Does anyone know if a topo map would exist for something like that? The USGS map that I see shows the lake outline but no contours inside the lake. I recall owning a USGS top map of Toledo Bend and it showed all the contours pre-impoundment, and it was impounded much later... in 1967. I don't know when the government crews came through this area... was it pre or post 1945.

EDIT:  Hmmm... if I click on the Toledo Bend area, I see a map same as above, it shows the lake boundary and no old contours pre-impoundment. So, not sure how to get the old contour maps. I will try to contact USGS.

I would start by telling us the name of the lake!