The river St. Croix taken in 1763 as the boundary of Nova Scotia and hence adopted as the boundary line in the Treaty of 1783.
The river St. Croix had always been a landmark in the history of colonization in North America. It was the scene of the first settlement by De Monts and Champlain; and, when Sir William Alexander in 1621 received from the King the famous grant of Nova Scotia, the grant was defined as extending to
‘the river generally known by the name of St. Croix and to the remotest springs, or source, from the Western side of the same, which empty into the first mentioned river’,
Later, the French claim on behalf of Acadia extended as far as the Penobscot river, if not to the Kennebec; but after the Treaty of Utrecht, the claims of Massachusetts to the country up to the St. Croix river were allowed in 1732;[230] and in 1763, after the Peace of Paris, the St. Croix river was, in the Commission to the Governor of Nova Scotia, designated as the boundary of the province, the following being the terms of the Commission:—
‘Although Our said province has anciently extended, and does of right extend, so far as the river Pentagoet or Penobscot, it shall be bounded by a line drawn from Cape Sable across the entrance of the Bay of Fundy to the mouth of the river St. Croix, by the said river to its source, and by a line drawn due North from thence to the Southern boundary of Our Colony of Quebec.’
Accordingly the river St. Croix was designated as the international boundary in the Treaty of 1783.
Doubt as to the identity of the St. Croix river.
But then the question arose which was the St. Croix river. Between 1763 and 1783 attempts had been made to identify it, but without success, for at least three rivers flowing into Passamaquoddy Bay were each claimed as the St. Croix. After the Peace of 1783, the dispute continued, and eventually the further Treaty of 19th of November, 1794, known from the name of the American statesman who negotiated it in London as Jay’s Treaty, provided in the Fifth Article that Commission appointed under the Treaty of 1794 to identify the river. the question should be left to the final decision of three Commissioners, one to be appointed by the British Government, one by that of the United States, and a third by the two Commissioners themselves. The article provided that
‘the said Commissioners shall by a Declaration under their hands and seals decide what river is the river St. Croix intended by the treaty. The said Declaration shall contain a description of the said river and shall particularize the latitude and the longitude of its mouth and its source.’