 The acquisition of Spanish claims to the Pacific Northwest also allowed the Monroe administration to pair the acquisition of Florida, which was chiefly sought by Southerners, with territorial gains favored primarily by those in the North.After extended negotiations, Spain and the United States agreed to the Adams–Onís Treaty, which was ratified in February 1821.Adams was deeply proud of the treaty, though he privately was concerned by the potential expansion of slavery into the newly-acquired territories.