(1842) Treaty between the U.S. and Britain establishing the northeastern boundary of the U.S. Negotiated by U.S. secretary of state Daniel Webster and Britain's ambassador Lord Ashburton, it also provided for Anglo-U.S. cooperation in the suppression of the slave trade.
It fixed the present boundary between Maine and New Brunswick, granted the U.S. navigation rights on the St. John River, provided for extradition in nonpolitical criminal cases, and established a joint naval system for suppressing the slave trade off the African coast.