The Collaborative International Dictionary of English v.0.48:

Furlong \Fur"long\, n. [OE. furlong, furlang, AS. furlang,
   furlung, prop., the length of a furrow; furh furrow + lang
   long. See Furrow, and Long, a.]
   A measure of length; the eighth part of a mile; forty rods;
   two hundred and twenty yards.
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Furlong
a stadium, a Greek measure of distance equal to 606 feet and 9
inches (Luke 24:13; John 6:19; 11:18; Rev. 14:20; 21:16).

U.S. Gazetteer (1990):

Furlong, PA
  Zip code(s): 18925