You will herewith receive a Commission giving you powers to adjust by proper stipulations with the British Government whatever remains to be decided in relation to the boundaries between the two nations.

In executing the first part of this trust relating to the Bay of Passamaquody you will recur to the observations contained in my letter of the 28th of July last.1 I refer you also to a copy herewith inclosed of a letter from Judge Sullivan,2 heretofore Agent of the United States on the controversy regarding the river St Croix, in answer to some enquiries from me on the subject now committed to you. His information and his reasoning will be useful in the discussion; and to illustrate both I also inclose herewith a copy of the Map to which he refers in the beginning of his letter.3

The essential objects to be secured to the United States are the jurisdiction of Moose Island and the common navigation of the Bay and of the channels leading towards the sea between Deer Island and the Island of Campo bello. To the observations of Judge Sullivan in support of the rights of the United States it need only be added that the outlet through those Islands being the only adequate communication with the sea from a great and valuable territory of the United States, they are entitled to the full use of it on that principle as well as on others; and with the less pretext for objection, as the trifling island of Campo bello is the only territory held by Great Britain on one side of the channel.

In pursuance of the next object, viz, the establishment of boundaries between the United States and New brunswick on one side and of Canada on another, it will be proper to provide for the immediate extension of the line which is to run from the source of the St Croix, and which is represented as necessary to guard against interfering or incroaching grants under american and British authorities. As the course of this line is to be due North, and is to proceed from the point fixed by a survey already made, the running of it will be sufficiently provided for by an appointment of a Commissioner by each of the two Governments, and an appointment by the two Commissioners of a surveyor. In fixing the point at which the line is to terminate, and which is referred to as the N. W. angle of Nova Scotia, the difficulty arises from a referrence of the Treaty of 1783 “to the Highlands,”4 which it is now found have no definite existence. To cure this difficulty, no better expedient occurs than to provide for the appointment of a third Commissioner as in Art: 5th of the Treaty of 1794,5 and to authorize the three to determine on a point most proper to be substituted for the description in the 2d Art: of the Treaty of 1783, having due regard to the general idea that the line ought to terminate on the elevated ground dividing the rivers falling into the atlantic from those emptying themselves into the St Laurence. The Commissioners may also be authorized, to substitute for the description of the boundary between the point so fixed and the Northwestermost head of Connecticut river, namely, a line drawn “along the said Highlands” such a referrence to intermediate sources of rivers, or other ascertained or ascertainable points, to be connected by straight lines, as will admit of easy and accurate execution hereafter, and as will best comport with the apparent intention of the Treaty of 1783. The remaining provision necessary to complete the boundary of the United States, will be a stipulation amending the 2d Art: of the Treaty of 1783 in its description of the line which is to connect the most Northwestern point of the Lake of the Woods, with the Mississippi. The description supposes that a line running due West from that point would intersect the Mississippi. It is now well understood the highest source of the Mississippi is South of the Lake of the Woods, and consequently that a line due West from its most Northwestern point would not touch any part of that river. To remedy this error, it may be agreed that the Boundary of the U. States in that quarter shall be a line running from that source of the Mississippi which is nearest to the Lake of the Woods, and striking it Westwardly as a tangent and from the point touched along the Water mark of the Lake to its most Northwestern point at which it will meet the line running thro’ the Lake. The map in McKensies late publication is probably the best to which I can refer you on this subject.6

From the mutual and manifest advantage to G. Britain and the U. States of an adjustment of all uncertainties concerning boundary, it is hoped you will find a ready concurrence in all the propositions which you will have to make to the Government of the former. Should difficulties or delays threaten those which relate to the boundary connecting the Mississippi and the Lake of the Woods, or that connecting Connecticut river and the point to be established as the N. East corner of the United States, it will be proper to separate from these the other subjects of negotiation, and to hasten the latter to a conclusion. With the highest respect & consideration I have the honor to be, Sir, your Obt Sert.