The Collaborative International Dictionary of English v.0.48:

Hayfield \Hay"field`\ (h[=a]"f[=e]ld`), n.
   A field where grass for hay has been cut; a meadow. --Cowper.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hayfield
    n 1: a field where grass or alfalfa are grown to be made into
         hay [syn: hayfield, meadow]

U.S. Gazetteer Places (2000):

Hayfield, MN -- U.S. city in Minnesota
   Population (2000):    1325
   Housing Units (2000): 519
   Land area (2000):     1.262403 sq. miles (3.269608 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.262403 sq. miles (3.269608 sq. km)
   FIPS code:            27872
   Located within:       Minnesota (MN), FIPS 27
   Location:             43.889175 N, 92.846049 W
   ZIP Codes (1990):     55940
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Hayfield, MN
    Hayfield