Pinckney's Treaty, also known as the Treaty of San Lorenzo, was signed in 1795 between the United States and Spain. The treaty aimed to resolve territorial disputes and secure navigation rights on the Mississippi River. It allowed American boats to travel freely along the river and access the port of New Orleans for trade. Additionally, the treaty established the boundary between the United States and Spanish Florida. This agreement helped to improve relations between the two nations and facilitated westward expansion for American settlers. Overall, Pinckney's Treaty was a significant diplomatic achievement for the early United States.