The 1821 census fragments are mentioned in Fermanagh Resources (stickied topic at top of Fermanagh board)-
Census Records & Census Substitutes
1821- only a few volumes for Co. Fermanagh survive (PRONI)- parish of Aghalurcher (townlands of Altamartin, Altamullaboy, Altdwark, Attaclenobrien, Aughavory, Augheetor, Carahoney, Cavanalack, Cleen, Colebrooke, Comnohy, Corlacky, Corrafat, Cran, Corckadreen, Currylongford, Derrintony, Derrychrum, Dordrany, Drumrock, Dunavoghy, Esnasillong, Esthomas, Feavanny, Foglish, Grogy, Killarbin, Killybawn, Lamphill, Legtiladay, Lisavinick, Moughly, Mount Gibbon, Owenskerry, Ranult, Stripe, Tatenahoglish, Tattyreagh, Tereaghan, Tullaharney, Tullichanie and Tulnavarin), Parish of Derryvullen (PRONI MIC/5A and MIC/15A).
(PRONI MIC/5A and MIC/15A) MIC/5A and MIC/15A are the microfilm reference for the material in PRONI, Belfast.
You can check the only LDS catalogue (
www.familysearch.org) to see if they also have a copy of the microfilm- if so, it's likely that for a small fee you can order it from your local LDS library to view there.