Most of the information I've seen has stated Fanny ALLIS-PROVIN died Sept. 2, 1864 in Wilson Co., KS.In going through the 1880 census at the LDS site, I found Fanny living in the household of her son, Joel Henry PROVIN. So now we know it was sometime after 1880 that Fanny died.
Ref: Pleasant Valley, Wilson Co., Kansas, page 129D Fanny PROVINMotherW(idowed)FemaleW89B. NY
Kaylynn CANTRALL / HARPER / NORTH / PROVIN All in DeWitt County, IL