The Free City of Tri-Insula was a proposed independent republic that would be formed out of the islands of Manhattan, Staten Island, and Long Island immediately prior to the United States Civil War. The idea was raised in early 1861 by New York City mayor Fernando Wood, who opposed the impending war between the United States and the Confederate States of America. According to him, war would adversely affect the New York economy because of the loss of cotton revenues.

The idea was rejected by the City Council and popular opinion.

(see: [1])