The Treaty of San Lorenzo, also known as the Pinckney Treaty, was signed on October 27, 1795, between the United States and Spain. This agreement aimed to resolve territorial disputes and establish friendly relations between the two nations. It granted the U.S. navigation rights on the Mississippi River and defined the boundary between Spanish Florida and the United States. The treaty was significant for American expansion, as it facilitated trade and settlement in the western territories. It also helped to ease tensions between the U.S. and Spain, promoting peace in the region during a time of growing American influence.