The Collaborative International Dictionary of English v.0.48:

Darby \Dar"by\ (d[aum]r"b[y^]), n.
   A plasterer's float, having two handles; -- used in smoothing
   ceilings, etc.
   [1913 Webster]

U.S. Gazetteer Places (2000):

Darby, MT -- U.S. town in Montana
   Population (2000):    710
   Housing Units (2000): 316
   Land area (2000):     0.531252 sq. miles (1.375936 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.531252 sq. miles (1.375936 sq. km)
   FIPS code:            19300
   Located within:       Montana (MT), FIPS 30
   Location:             46.022030 N, 114.179603 W
   ZIP Codes (1990):     59829
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Darby, MT
    Darby


U.S. Gazetteer Places (2000):

Darby, PA -- U.S. borough in Pennsylvania
   Population (2000):    10299
   Housing Units (2000): 3999
   Land area (2000):     0.815793 sq. miles (2.112894 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.815793 sq. miles (2.112894 sq. km)
   FIPS code:            18152
   Located within:       Pennsylvania (PA), FIPS 42
   Location:             39.918312 N, 75.258360 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Darby, PA
    Darby