The Collaborative International Dictionary of English v.0.48:

Gerrymander \Ger`ry*man"der\, v. t. [imp. & p. p.
   Gerrymandered; p. pr. & vb. n. Gerrymandering.]
   To divide (a State) into districts for the choice of
   representatives, in an unnatural and unfair way, with a view
   to give a political party an advantage over its opponent.
   [Political Cant, U. S.]
   [1913 Webster]

   Note: This was done in Massachusetts at a time when Elbridge
         Gerry was governor, and was attributed to his
         influence, hence the name; though it is now known that
         he was opposed to the measure. --Bartlett.
         [1913 Webster]