The Americans acquired their territory in four great expansions. The first of these resulted from the negotiation of peace following the revolutionary war. After the British surrender at Yorktown on 19 October 1781, talk of peace spread in Paris and London and informal exchanges began between representatives of both sides. (The Continental Congress in Philadelphia had been considering peace terms since 1779.) Talks stipulated the unqualified declaration of American independence as the first prerequisite and laid out extensive boundaries. While some members wanted to ask for all of Canada, the negotiating terms mentioned only the Ontario peninsula to the north, between Lakes Huron, Erie, and Ontario (the "Nipissing line") and territory around the Great Lakes as far west as the source of the Mississippi River. To the south, they optimistically included the eastern half of the Mississippi Valley down to 31 degrees, the northern limit of Spanish Florida and Louisiana. Cession of this lower valley was certain to be unacceptable to the ministers of France and especially Spain, who wanted to protect their nations' territory by shutting up the Americans east of the Appalachians. Agents of the two countries put pressure on Congress over the next two years with the result that by the Battle of Yorktown, instructions of June 1781 from Congress required the American peace commissioners to consult the French foreign minister, the Comte de Vergennes, on all matters except independence.
The Continental Congress named five commissioners to start negotiations, but only three played any active roles: Benjamin Franklin, John Adams, and John Jay, who were already in Europe seeking loans and other aid. They had good reason to suspect the motives of their European allies, especially Jay and Adams. They were also aware of more conciliatory feeling in some British circles, especially one minister who was rising to a leading position in the government. This was Lord Shelburne, who saw a chance to attract the Americans away from Vergennes, renew the formerly prosperous Anglo-American trade relations, and perhaps eventually restore some sort of imperial political connection.
The first half of 1782 was a time of rumor and confusion in both London and Paris. Shelburne became prime minister, but the British and French continued naval warfare in the Caribbean, and King George kept up his stubborn refusal to recognize the colonies' independence. The American commissioners concluded that it would be more rewarding to negotiate separately with Britain and avoid Vergennes's interference, although the alliance treaty specified a joint settlement. A breakthrough came when John Jay received what he thought was evidence that France and Spain intended to make a private agreement on boundaries in the Ohio Valley to restrain the Americans. Without informing Franklin, the most pro-French of the trio, Jay sent an agent to Shelburne to argue for a Mississippi River boundary and indicate that he and his colleagues would negotiate separately for preliminary terms. Franklin approved Jay's action, and so did Adams, who arrived in Paris several weeks later from his own mission in the Netherlands.
Negotiation of a preliminary treaty took place during October and November 1782. Jay wrote the basic draft, but Adams, Franklin, and the British negotiators made so many changes and argued so heatedly that each major historian has assigned a different set of credits for individual sections. Recognition of American independence caused little trouble, but Franklin, who had always wanted to annex as much of Canada as possible, had to give up the Ontario peninsula. In its place he accepted an irregular boundary along the midpoints of four Great Lakes and a series of rivers and lakes west to the source of the Mississippi River. Unfortunately, this line missed the river, creating a gap that was not closed until 1818. In the interim, the British retained theoretically the right to navigate the river. The boundary then ran down the Mississippi to 31 degrees and eastward along that line and a nearby parallel to the St. Marys River and the Atlantic Ocean. The Americans' greatest territorial gain was the eastern half of the Mississippi Valley, a true seat of empire. However, a secret article (largely written by Jay) offered Britain another line north of 31 degrees as an inducement to retain the Florida coast and peninsula instead of turning it over to Spain. With Canada still a British colony, this would have put America's Atlantic trade in a pincer and kept Florida indefinitely out of its hands. (Fortunately, Spain, failing to recover Gibraltar in Europe, demanded Florida in its place.)
The preliminary articles disposed of the most important boundary questions, so the remaining discussions dealt with other matters. The most important of these were the colonial debts owed to British creditors, the treatment of loyalists living in America or owning property there, and the New England fisheries, concerning which Adams played the dominant role. Since nearly all of western Europe had been involved in the war, the British had accounts to settle elsewhere. This sometimes worked to the advantage of the Americans by distracting the British from North American affairs or placing an extra premium on American friendship. The American commissioners were shrewd men of the world who took advantage of every opening offered them. (Adams and Jay were lawyers, Franklin a businessman and bureaucrat.)
During the two decades after the revolutionary war the major problems affecting U.S. foreign relations were commerce and western settlements. The British had recognized the irregular line along the Great Lakes as the northern boundary. However, even as the king signed the treaty, providing that the chain of border forts on American territory from Ogdensburg west to Mackinac should be evacuated "with all convenient speed," his home secretary was issuing an order saying in effect, "take your time." The cabinet in London was concerned about the future of the international fur trade and peaceful relations with the Indians north of the border, and it anticipated that the Americans would commit other treaty violations and thereby justify the retention of the forts. Not surprisingly, however, the suspicious Americans assumed that the British were trying to hold onto the West. In the early 1790s, when the British resumed fighting with the French, their violations of American neutrality reinforced the complaints of western settlers about British soldiers in the border forts and brought on a major crisis. In 1794, John Jay negotiated a treaty that averted a probably disastrous war by bringing about the evacuation of the forts and securing a few commercial concessions. For other reasons, Jay's treaty was highly unpopular and cost him his reputation, but it confirmed Americans' occupation of their northern frontier, especially since a victory over the Indians in northwest Ohio at the same time discredited the traditional allies of the British.
Just as important to the growth of the American West was its boundary on the lower Mississippi, into which all the valley's rivers drained, so that the entire trade of the area was funneled through New Orleans. When the Spanish took over control of the Gulf of Mexico coast from the British under the 1783 treaty, they tried to anticipate the flow of American settlers over the Appalachian Mountains by a number of defensive strategies. First, they encouraged the Indian nations of Georgia, Alabama, and Mississippi to form a buffer, but the development of trade with the Americans and the lack of Indian cohesiveness frustrated this effort. In the late 1780s they sent an emissary to persuade the American government to give up its efforts to open the lower Mississippi to trade in return for concessions to Americans trading across the Atlantic. However, the southern states (which had no large seaports but many western connections) formed a solid bloc in opposition. Finally, the Spanish government intrigued western leaders to secede and become a Spanish protectorate. A few, such as James Wilkinson, nibbled at the bait, but by this time the Constitutional Convention of 1787 fore-shadowed a new government, strong enough to defend American interests in the West, and the Spanish efforts died out.
Although the Spanish could not prevent the migration of American settlers into the eastern Mississippi Valley, they denied them the right to ship their goods downriver to New Orleans and built several forts on the east bank, which they claimed as far north as the junction with the Ohio. The Americans, who held title to the east bank only from the British, had to wait and watch while Spanish politics moved languidly to and fro according to the progress of the French Revolution, then in its radical phase. From 1793 to 1795, Spain was actually an ally of its old enemy Britain against the Jacobins. In 1795 the Spanish withdrew from the war and indicated that they were ready to negotiate with the Americans—perhaps because they were nervous about the significance of the recent American Jay's Treaty with the British or because they had abandoned hope of stopping their westward migration. (Historians are still unsure.) The result was Pinckney's Treaty (1795), which was so popular that the Senate approved it unanimously. In it Spain recognized the 31-degree boundary and agreed to evacuate its forts (although this took two years). It also granted the Americans the right to navigate the lower Mississippi and warehouse their goods on shore while awaiting ocean shipment (the "right of deposit").
Like Jay's Treaty, Pinckney's Treaty confirmed an earlier expansion by giving the United States control over its borders. As Americans poured into the new states of Kentucky, Tennessee, and Ohio, they shipped their products down the Mississippi to New Orleans and out into the Gulf of Mexico and the ocean to the east coast and Europe. American attention turned again to the Atlantic world, and the United States fought a brief naval war with France over neutral rights, which formally ended the alliance between the two countries but did no serious damage to either one. A new leader in France, Napoleon Bonaparte, won victories over most of western Europe and signed a temporary truce with Britain.