On the Niagara River, U.S. naval units arrest Fenian invaders as they retreat back into the United States
Intending to force British concessions in Ireland, Fenian infantry under Union Army veteran Colonel John O'Neill had crossed the Niagara River into Ontario. After defeating Canadian militia at Ridgeway and Waterloo the day before, O'Neill decided to retreat back across the border but a large number of his men were arrested crossing the Niagara by U.S. naval units enforcing the Neutraility Act of 1819. (By John Osborne)
Patrick Steward, Bryan P. McGovern, The Fenians: Irish Rebellion in the North Atlantic World, 1858–1876 (Knoxville, TN: University of Tennessee Press, 2013), 131-132.