If you are interested in old maps, take a look at the website oldmapsonline.org .
You can type in the name of a town and then scroll through different time periods to see maps of that area. I found an 1817 map showing Fort Miro and what I assume is a building symbol showing where the Catholic church was! If you like looking at old maps, you could spend hours exploring this website!
Ouachita Parish History Tidbits 