The Arkansas Census records at Access Genealogy have been updated.
The census directory provides the researcher with the most current records available online for free, and clearly annotates when there are no records available for that census year for free, and provides links to paid sources instead. The census was first taken in Arkansas in 1810 while it was still part of a territory of the United States and not an actual state. A series of "sherriff" census were taken in the 1820's of which only a few survive. Those that do survive however, shine a light on the names of the early settlers.
The first full census taken in Arkansas in which we have records of was the Arkansas 1830 Census. From then on, every 10 year, census have been taken as required by Congress. Of those census, the 1830-1930 are now all available online. The 1940 should become available in 2012.
The 1890 Arkansas census was lost to fire, as was almost the entire 1890 census. Efforts have been made to replicate that census, but these pale in comparison to the value that the 1890 would have provided the researcher.
Visit: Arkansas Census Records