The Caroline Affair (1837-1842) began when, on the U.S. shore of the Niagara River near Buffalo, Canadian authorities seized and burned the American vessel Caroline. The ship was leased to run supplies to Navy Island for the support of Canadian revolutionaries led by William Lyon MacKenzie. In the fracas an American was killed by a Canadian militiaman. Ultimately the Canadian was acquitted.

Webster-Ashburton Treaty (1842)