2023 New York Laws › STL - State › Article 2 - State Boundaries › 5 - Canada Boundary Line.

§ 5. Canada  boundary line. The boundary line between the state of New
  York and Canada is as follows:
Commencing at the intersection of  the  parallel  of  the  forty-fifth
  degree  of  north latitude with the middle of the deepest channel of the
  Richelieu river and running  thence  westerly  along  said  parallel  of
  forty-five  degrees  north  latitude  as originally run by Valentine and
  Collins, 1771-1774, to a point on the south shore of  the  St.  Lawrence
  river  (but  shown by the United States survey of boundary line in 1845,
  under treaty of Washington, 1842, on sheet maps XXVI to XXX to vary from
  true parallel of forty-five degrees, as follows: monument 645,  on  bank
  of Richelieu river, is .822 miles north of parallel of 45° and .02 miles
  west  from  river;  thence westerly 14.68 miles to monument 673, at .336
  miles north; thence westerly 6.56 miles to monument 685, at  .353  miles
  north;  thence westerly 9.20 miles to monument 703, at .004 miles south;
  thence westerly 7.43 miles to monument 717, at .429 miles south;  thence
  westerly  10.02  miles  to  monument  737,  at  .475 miles south; thence
  westerly 6.34 miles  to  monument  749,  at  .140  miles  south;  thence
  westerly  5.88  miles  to  monument 762, on true parallel of 45°; thence
  westerly 4.20 miles to monument 774, at .030 miles north on bank of  St.
  Lawrence river S. 74° 45' W. 1840 yards distant from the stone church in
  the  Indian  village  of  St.  Regis,  this line being recognized as the
  boundary line by article one  of  said  treaty  of  Washington).  Thence
  beginning  at  aforesaid  point on the south shore of the Saint Lawrence
  river, marked by monument 774, under the treaty of Washington, 1842, and
  in 1817 by a stone monument erected by Andrew Ellicott (the location  of
  which point is described above), and running north 35° 45' west into the
  river, on a line at right angles with the southern shore, to a point 100
  yards  south  of  the  opposite  island,  called Cornwall island; thence
  turning westerly and passing around the southern  and  western  side  of
  said  island  keeping  100  yards  distant  therefrom, and following the
  curvatures of its shores, to a point opposite to the northwest corner or
  angle of said island; thence to and along the middle of the  main  river
  until  it  approaches the eastern extremity of Barnhart's island; thence
  northerly along the channel which divides the last mentioned island from
  the Canada shore, keeping 100 yards distant from the  island,  until  it
  approaches  Sheik's  island; thence along the middle of the strait which
  divides Barnhart's and Sheik's islands to the channel  called  the  Long
  Sault,  which  separates  the  two last mentioned islands from the lower
  Long Sault island; thence westerly (crossing  the  center  of  the  last
  mentioned  channel)  until  it  approaches within 100 yards of the north
  shore of the Lower Sault island; thence up the north branch of the river
  keeping to the north of and near the Lower Sault island, and also  north
  of and near the Upper Sault, sometimes called Baxter's island, and south
  of  the  two  small  islands  marked  on the map A and B, to the western
  extremity of the Upper Sault or Baxter's island; thence passing  between
  the  two  islands  called  the  Cats,  to the middle of the river above;
  thence along the middle of the river, keeping to the north of the  small
  islands marked C and D, and north also of Chrystler's island, and of the
  small  island next above it, marked E, until it approaches the northeast
  angle of Goose Neck island; thence along the passage which  divides  the
  last  mentioned island from the Canada shore, keeping 100 yards from the
  island to the upper end of the same; thence south of and  near  the  two
  small  islands  called  the  Nut  islands;  thence north of and near the
  island marked F, and also of the island called Dry or Smuggler's island;
  thence passing between the islands marked G and H to the  north  of  the
  island  called  Isle  au Rapid Platt; thence along the north side of the
  last mentioned island, keeping 100 yards from the shore,  to  the  upper
  end  thereof; thence along the middle of the river, keeping to the south

  of and near the islands called Coussin (or  Tussin)  and  Presque  isle;
  thence  up the river, keeping north of and near the several Gallop Isles
  numbered on the map, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, and also of Tick,
  Tibbits,  and  Chimney  islands,  and south of and near the Gallop isles
  numbered 11, 12 and 13, and also of Duck, Drummond, and  Sheep  islands;
  thence  along  the  middle of the river, passing north of island No. 14,
  south of 15 and 16, north of 17, south of 18, 19, 20, 21, 22, 23, 24, 25
  and 28, and north of 26 and 27; thence along the middle  of  the  river,
  north  of  Gull island and of the islands Nos. 29, 32, 33, 34, 35, Bluff
  island, and Nos. 39, 44 and 45, and to the south of  Nos.  30,  31,  36,
  Grenadier  island,  and Nos. 27, 28, 40, 41, 42, 43, 46, 47 and 48 until
  it approaches the east end of Wells island, thence to the north of Wells
  island, and along the  strait  which  divides  it  from  Rowe's  island,
  keeping  to  the north of the small islands Nos.  51, 52, 54, 58, 59 and
  61, and to the south of the small islands numbered and  marked  49,  50,
  53,  55,  57,  60,  and  X,  until  it approaches the northeast point of
  Grindstone island; thence to the north of Grindstone island and  keeping
  to  the north also of the small islands Nos. 63, 65, 67, 68, 70, 72, 73,
  74, 75, 76, 77 and 78, and to the south of Nos. 62, 64, 66, 69  and  71,
  until it approaches the southern point of Hickory island; thence passing
  to  the  south of Hickory island and of the two small islands lying near
  its southern extremity numbered 79 and 80; thence to the south of  Grand
  or  Long  island,  keeping  near  its southern shore, and passing to the
  north of Carlton island, until it arrives opposite to  the  southwestern
  point,  of  said  Grand  island, in Lake Ontario; thence, passing to the
  north of Grenadier, Fox, Stony, and the Gallop islands, in Lake Ontario,
  and to the south of and near the islands called the Ducks, to the middle
  of the said lake, thence westerly along the middle of  said  lake  to  a
  point  opposite  the  mouth  of  the Niagara river, thence to and up the
  middle of the said river to the Great Falls; thence up the Falls through
  the point of the Horse Shoe, keeping  to  the  west  of  Irish  or  Goat
  island, and of the group of small islands at its head, and following the
  bends  of  the  river  so  as to enter the strait between Navy and Grand
  islands; thence along the middle of said strait  to  the  head  of  Navy
  island;  thence  to  the  west and south of and near to Grand and Beaver
  islands, and to the west of Strawberry, Unity, and Bird islands to  Lake
  Erie;  thence  southerly and westerly along the middle of Lake Erie in a
  direction to enter the passage immediately south of Middle island, being
  one of the easternmost of the group of islands lying in the western part
  of said lake (according to the decision of the commissioners  under  the
  sixth  article of the treaty of Ghent, 1814, done at Utica, state of New
  York, June 18, 1822) to intersection  with  meridian  line  of  Cession,
  drawn  through  the  most  westerly bent or inclination of Lake Ontario,
  under deed of cession to the United  States,  executed  March  1,  1781,
  under  chapter  thirty-eight  of the third session of the legislature of
  this state in 1780, which meridian line was  surveyed  and  marked  with
  monuments by Andrew Ellicott in 1790, as duly appointed under resolution
  of  Congress, August 19, 1789, and resurveyed in 1881 to 1885, and final
  report made December 1, 1885,  by  H.  W.  Clarke,  civil  engineer  and
  surveyor, on the part of the state of New York.