2006 New York Code - Apportionment Of Division Fence.

 
    §  300.  Apportionment  of division fence. Each owner of two adjoining
  tracts of land,  except  when  they  otherwise  agree,  shall  make  and
  maintain a just and equitable portion of the division fence between such
  lands,  unless  both  of  said adjoining owners shall agree to let their
  said lands lie open, along the division line, to the use of all  animals
  which  may be lawfully upon the lands of either; provided, however, that
  the owner of an adjoining tract of land who does not keep  such  animals
  thereon  within  five  years  of the date of the erection or repair of a
  division  fence  shall  not  be  obligated  or  liable   for   erecting,
  maintaining  or  repairing  such  a  division  fence under this article.
  Unless otherwise agreed, an adjoining owner  who  erects  or  repairs  a
  division  fence shall be entitled to recover from the owner of the other
  adjoining tract,  twenty  percent  of  the  proportionate  cost  thereof
  otherwise  ascribable  to such other owner for each year or part thereof
  in which the other adjoining tract is regularly used for keeping animals
  occurring within five years of the date of such erection or repair. When
  the adjoining lands shall  border  upon  any  of  the  navigable  lakes,
  streams  or  rivers of the state, the owners of the lands shall make and
  maintain the division fence between them down to the line of  low  water
  mark, in such lakes, streams or rivers except those lands which overflow
  annually so as to be so submerged with water that no permanent fence can
  be  kept  thereon, and known as low flat lands; and when adjoining lands
  shall be bounded by a line between the banks of  streams  of  water  not
  navigable,  and  the  owners  or occupants thereof cannot agree upon the
  manner in which the division fence between them shall be maintained, the
  fence viewers of the town shall direct upon which bank  of  the  stream,
  and  where  the  division  fence shall be located, and the portion to be
  kept and maintained by each adjoining owner.