I was interested in knowing what Ouachita Parish items are in other collections around the country and was surprised at what I found!
Isaiah Garrett’s business ledger is at the University of Alabama: https://archives.lib.ua.edu/repositories/3/resources/4802
Sarah Lois Wadley’s diary and the papers of the Ladies Aid Society of Ouachita Parish are at the University of Chapel Hill, North Carolina:
https://finding-aids.lib.unc.edu/01258/
Notre Dame University has many Ouachita Post papers, including the trial of Jean Filhiol for performing unauthorized marriages:
http://archives.nd.edu/mano/default.htm
The Special Collections Department of University of Louisiana at Monroe has some treasures. Of particular interest is their photos of Northeast Louisiana, which has some great shots of early one room schools in the parish:
https://www.ulm.edu/library/archives/index.html
Xavier University has some priceless slave documents from the McEnery and Breard families:
https://cdm16948.contentdm.oclc.org/digital/collection/p16948coll6/search/searchterm/Ouachita
Tulane has the Cooley family papers, as well as the Confederate Hospital ledger book:
Louisiana State University has some Filhiol, Baron deBastrop and Maison Rouge papers in their J. Fair Hardin collection (among other things!):