The Collaborative International Dictionary of English v.0.48:

Selden \Sel"den\ (s[e^]l"den), adv.
   Seldom. [Obs.] --Chaucer.
   [1913 Webster]

U.S. Gazetteer Places (2000):

Selden, NY -- U.S. Census Designated Place in New York
   Population (2000):    21861
   Housing Units (2000): 7083
   Land area (2000):     4.655753 sq. miles (12.058345 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    4.655753 sq. miles (12.058345 sq. km)
   FIPS code:            66212
   Located within:       New York (NY), FIPS 36
   Location:             40.870914 N, 73.047020 W
   ZIP Codes (1990):     11784
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Selden, NY
    Selden


U.S. Gazetteer Places (2000):

Selden, KS -- U.S. city in Kansas
   Population (2000):    201
   Housing Units (2000): 118
   Land area (2000):     0.301824 sq. miles (0.781721 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.301824 sq. miles (0.781721 sq. km)
   FIPS code:            63875
   Located within:       Kansas (KS), FIPS 20
   Location:             39.541194 N, 100.567064 W
   ZIP Codes (1990):     67757
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Selden, KS
    Selden