On January 13, 1838, Mackenzie abandoned Navy Island under heavy fire from British troops. He and his force retreated to Buffalo, New York, where they were captured by the U.S. army and sentenced in the U.S. to 18 months' imprisonment for violating neutrality laws between the United States and the United Kingdom, ending the prospect of a Canadian declaration of independence/secession and ending what the British authorities described as an inconsequential and unsupported colonial rebellion.