Final answer:
Pinckney's Treaty (1795) with Spain gave the United States the right to navigate the Mississippi and the right of deposit in New Orleans.
Step-by-step explanation:
The significance of Pinckney's Treaty (1795) with Spain is that it gave the United States the right to navigate the Mississippi and the right of deposit in New Orleans. This allowed American farmers to ship their products down the Ohio and Mississippi Rivers to New Orleans, where they could be transported to East Coast markets.