The Collaborative International Dictionary of English v.0.48:

Insularity \In`su*lar"i*ty\, n. [Cf. F. insularit['e].]
   [1913 Webster]
   1. The state or quality of being an island or consisting of
      islands; insulation.
      [1913 Webster]

            The insularity of Britain was first shown by
            Agricola, who sent his fleet round it. --Pinkerton.
      [1913 Webster]

   2. Narrowness or illiberality of opinion; prejudice;
      exclusiveness; as, the insularity of the Chinese or of the
      aristocracy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

insularity
    n 1: the state of being isolated or detached; "the insulation of
         England was preserved by the English Channel" [syn:
         insulation, insularity, insularism, detachment]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "insularity":
   Jim Crow, ait, alien, apartheid, archipelago, atoll,
   authoritarianism, bar, bigotry, blind side, blind spot, blinders,
   cay, closed mind, color bar, continental island, coral head,
   coral island, coral reef, cramped ideas, division, ethnocentrism,
   exclusiveness, fanaticism, foreigner, hideboundness, holm,
   illiberality, insularism, insulation, island, island group,
   islandology, isle, islet, isolation, key, know-nothingism,
   little-mindedness, littleness, mean mind, meanness,
   narrow sympathies, narrow views, narrow-mindedness, narrowness,
   nearsightedness, oceanic island, odium theologicum, out-group,
   outcast, outsider, parochialism, persona non grata, pettiness,
   petty mind, provincialism, purblindness, quarantine, race hatred,
   racial segregation, reef, sandbank, sandbar, seclusion,
   segregation, separation, shortsightedness, shut mind, smallness,
   snobbishness, straitlacedness, stranger, stuffiness, tightness,
   uncatholicity, xenophobia