Hartford Convention, a meeting of New England Federalists at Hartford, Connecticut, during the War of 1812. It met from December 15, 1814, to January 5, 1815. The purpose was to express grievances against President James Madison's administration and against the war, and to safeguard the interests of New England against the South and West. Its proceedings were conducted in secret.

The Federalists were embittered because they had been out of power since 1801. They represented the commercial interests of New England, and opposed the agricultural South and West. The democratic West was gaining strength with the admission of new states. New England commerce was losing ground to manufacturing.

New England Federalists denounced “Mr. Madison's war” as ruinous to their commerce. They discouraged enlistments and opposed the use of their militia for national service. On October 18, 1814, the Massachusetts legislature proposed a convention to initiate revision of the U.S. Constitution. The resulting Hartford Convention had 26 delegates: 12 from Massachusetts, 7 from Connecticut, 4 from Rhode Island, 2 from New Hampshire, 1 from Vermont.

The convention gave no support to suggestions for secession. Its report stated New England's grievances, attacked Madison's administration, and denounced the war. Several constitutional amendments were proposed. The proposals, if adopted, would have supported states' rights, weakened the federal government, limited the political power of the South, made admission of new states more difficult, and restricted holding of public office by naturalized citizens.

The Treaty of Ghent, signed December 24, 1814, brought peace and an end to the worst of the grievances. In the wave of patriotism that followed, the Hartford Convention was denounced as a step toward treason. The Federalist party was discredited and soon disappeared. But the movement had given support to the doctrines of states' rights and nullification.