From surveying historical aerials, I believe this bridge predates US 71 and was in fact part of the Jefferson Highway. The 1955 aerial shows the current bridge with a one lane road using this bridge. This would confirm a build date of the mid to late 1910s or very early 1920s.
Drove by this bridge yesterday. Sagging very heavily in the middle; much more pronounced than in the current photos. I wouldn't walk across it if I stopped. Maybe I'll get pictures next time. Didn't think to snap them as I cruised by, though I did get some of the Hudson Creek bridge.
This is a really nice find with great photos. Good hunting.
I'm also pretty sure this bridge was built in the 1920s or earlier, though I'm kinda leary of trusting NBI's date for the current bridge (which is listed as being built in 1931). If the "new" bridge is truly a 1930s product then this bridge could be from the teens, though based on the peer designs I wouldn't be surprised if it was built in the 30s and the currently-used bridge is a product of a later date. The old road bed of US 71 can be followed for a long way from Grant Parish northward.
Basically, it doesn't make much sense for a solid concrete bridge to be built in the teens and then abandoned 20 years later.
I'm pretty sure these are the accurate coordinates for this bridge:
Check out street view and you can see what looks like a bridge in the woods.
Its been a few years since I last drove 71 but I think there's another, similar abandoed bridge to the east of the road further to the south.... next time I head tht way I'll double check.