For more information about census schedules:
While online searching is now the easiest way to located specific names there are printed indexes to the population schedules.
For 1920 and 1930, the Libraries have a Soundex index to names located at Library Annex LISA Microfilm F 410 .I52 920a and F 410 .I52 1930a.
There are a number of specialized indexes for individual counties in Special Collection; these can be found by searching the Library Catalog under the subject [county name] ark--census, e.g., "Johnson County Ark --Census--1860."
Published census materials covering 1790-2010, which would usually provide county-level data for Arkansas, can be found in the GovRef Census collection on Level Four of Mullins Library as well as online through the Census Bureau website.