France–United States relations

The Kingdom of France was the first country to have diplomatic ties with the new United States in 1778. The 1778 Treaty of Alliance between the two countries and the subsequent aid provided from France proved decisive in the American victory over Britain in the American Revolutionary War. France, however, was left heavily indebted after the war, which contributed to France's own revolution and eventual transition to a republic.

The France–United States relations has remained peaceful since, with the exceptions of the Quasi-War from 1798 to 1800 and American combat against Vichy France (while supporting Free France) from 1942 to 1944 during World War II. In 1803, the United States purchased the territory of Louisiana from France to acquire a total of 828,000 sq mi (2,140,000 km²; 530,000,000 acres) and expand westwards. Tensions, however, rose during the American Civil War, as France intervened militarily in Mexico and entertained the possibility of recognizing the separatist Confederate States of America, the defeat of which was followed by the United States sending a large army to the Mexican border and forcing the withdrawal of French forces from Mexico.

Since 2000, the United States and France have continued to work together on a range of issues, such as counterterrorism, climate change, and trade. However, there was sharp disagreement over the Iraq War in 2003. Relations improved again starting in 2010. In 2024, upon appointing a new U.S. ambassador to France, President-elect Donald Trump called France "our oldest ally, and one of our greatest".