Rackensack is an early nickname for the state of Arkansas.  The derivation of the word has been analyzed with no single, sure source ever identified.  By the end of the 1840's Rackensack was established as a burlesque synonym for rural Arkansas, particularly the hills of the western part of the state, which includes Washington County.  

Source for information is the Encyclopedia of Arkansas History & Culture, www.encyclopediaofarkansas.net