The United States purchased France's claim to the Louisiana Territory for 80 million francs, or less than US$.03 per acre ($.07/ha).

The Louisiana Purchase was the acquisition of the territory of Louisiana by the United States from the French First Republic in 1803. This consisted of most of the land in the Mississippi River's drainage basin west of the river. In return for fifteen million dollars, or approximately eighteen dollars per square mile ($7/km²), the United States nominally acquired a total of 828,000 sq mi now in the Central United States. However, France only controlled a small fraction of this area, most of which was inhabited by Native Americans; effectively, for the majority of the area, the United States bought the preemptive right to obtain Indian lands by treaty or by conquest, to the exclusion of other colonial powers.

Louisiana, also known as French Louisiana, was a district of New France. In 1682, the French explorer René-Robert Cavelier, Sieur de la Salle erected a cross near the mouth of the Mississippi River and claimed the whole of the drainage basin of the Mississippi River in the name of King Louis XIV, naming it "Louisiana". This land area stretched from near the Great Lakes to the Gulf of Mexico and from the Appalachian Mountains to the Rocky Mountains. The area was under French control from 1682 to 1762 and in part from 1801 (nominally) to 1803.

The franc, also commonly distinguished as the French franc (FF), was a currency of France. Between 1360 and 1641, it was the name of coins worth 1 livre tournois and it remained in common parlance as a term for this amount of money. It was reintroduced in 1795. After two centuries of inflation, it was redenominated in 1960, with each new franc (NF) being worth 100 old francs. The NF designation was continued for a few years before the currency returned to being simply the franc. Many French residents, though, continued to quote prices of especially expensive items in terms of the old franc, up to and even after the introduction of the euro in 2002. The French franc was a commonly held international reserve currency of reference in the 19th and 20th centuries. Between 1998 and 2002, the conversion of francs to euros was carried out at a rate of 6.55957 francs to 1 euro.