The Treaty of San Lorenzo, also known as Pickney’s Treaty, was signed on this date in 1795, in San Lorenzo de El Escorial, Spain. The treaty’s full title is Treaty of Friendship, Limits, and Navigation Between Spain and the United States. Thomas Pinckney negotiated the treaty for the United States and Don Manuel de Godoy represented Spain.
It was later ratified in the United States on March 7, 1796, and officially proclaimed by both countries on August 3, 1796. The treaty defined borders between Spanish and American territories and also granted the United States navigation rights to the Mississippi River. Spain had acquired Florida from Great Britain in the Treaty of Peace, ending the American Revolutionary War and beginning an almost forty-year period of rule known as the Second Spanish Period.
A joint American and Spanish survey team set the northern boundary of Florida at 31 degrees north latitude, starting from the Mississippi River, moving east to the St. Marys River, and out to the Atlantic. The treaty strengthened the American presence in the southeast, and although it helped to settle some early boundary disputes, Spain and the United States argued over borders until the U.S. acquired the Florida territories in 1821.
~Florida Historical Society