His determination so impressed the Spanish Government that it finally consented to a treaty, October 27, 1795, which fixed the southern boundary of the United States and opened the Mississippi River to navigation.

The boundary line was to run east along the thirty-first parallel of latitude from the Mississippi to the Appalachicola, thence along the latter river to its junction with the Flint, thence to the headwaters of the St.Mary's, and along its course to the Atlantic Ocean.
The free navigation of the Mississippi was coupled with the privilege of depositing merchandise at New Orleans "without paying any other duty than a fair price for the hire of the stores." This privilege was to be continued after three years, or "an equivalent establishment" on the banks of the Mississippi was to be assigned to citizens of the United States--a provision which was not free from ambiguities and which furnished fresh material for controversy a few years later..