The Collaborative International Dictionary of English v.0.48:

Pocoson \Po*co"son\, n.
   Low, wooded grounds or swamps in Eastern Maryland and
   Virginia. [Written also poquoson.] --Washington.
   [1913 Webster]

U.S. Gazetteer Counties (2000):

Poquoson -- U.S. city in Virginia
   Population (2000):    11566
   Housing Units (2000): 4300
   Land area (2000):     15.516153 sq. miles (40.186651 sq. km)
   Water area (2000):    62.908878 sq. miles (162.933240 sq. km)
   Total area (2000):    78.425031 sq. miles (203.119891 sq. km)
   Located within:       Virginia (VA), FIPS 51
   Location:             37.133153 N, 76.373881 W
   Headwords:
    Poquoson
    Poquoson, VA
    Poquoson city
    Poquoson city, VA


U.S. Gazetteer Places (2000):

Poquoson, VA -- U.S. city in Virginia
   Population (2000):    11566
   Housing Units (2000): 4300
   Land area (2000):     15.516153 sq. miles (40.186651 sq. km)
   Water area (2000):    62.908878 sq. miles (162.933240 sq. km)
   Total area (2000):    78.425031 sq. miles (203.119891 sq. km)
   FIPS code:            63768
   Located within:       Virginia (VA), FIPS 51
   Location:             37.133153 N, 76.373881 W
   ZIP Codes (1990):     23662
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Poquoson, VA
    Poquoson