Louisiana Purchase — 30 avril 1803

Two and a half million square kilometres were ceded to the United States for fifteen million dollars, some eighty million francs. The failure in Saint-Domingue had ruined the project of an American empire, and the renewal of war with London made the colony indefensible. Bonaparte thus financed his army and, in his own words, gave England 'a maritime rival'.

A colony France had only just taken back

Louisiana had been ceded to Spain in 1762. Bonaparte had it secretly retroceded by the Treaty of San Ildefonso in 1800, as part of a grand American design: Saint-Domingue would produce sugar, Louisiana would feed it with wheat and timber, and New Orleans would command the mouth of the Mississippi.

The project collapsed with the Saint-Domingue expedition, destroyed by war and yellow fever. Without the West Indies, Louisiana had no function; and without a navy it was indefensible once war with London resumed, as it then seemed about to.

Thirty days of negotiation

Jefferson had sent Robert Livingston and James Monroe to Paris only to buy New Orleans and secure free navigation of the river. Barbé-Marbois, minister of the Treasury, offered them the whole territory instead. The treaty was signed in Paris on 30 April 1803.

The total price came to fifteen million dollars, some eighty million francs: sixty million paid to France in bonds placed by the Baring and Hope banks, and twenty million corresponding to the claims of American citizens on France, which the United States took over.

Doubling the United States

More than two million square kilometres changed hands — the Missouri basin and the west bank of the Mississippi, today all or part of some fifteen states. The area of the Union doubled at a stroke.

Jefferson, a strict constructionist, publicly doubted that he had the right to acquire territory; the Senate ratified nonetheless that autumn. The Lewis and Clark expedition set out to survey the purchase in 1804. For Bonaparte the operation financed the coming war and, in his own words, gave England a maritime rival.