Establishing Boundaries for Spanish West Florida is No Simple Matter. Under consideration is not the entire province of Spanish West Florida stretching to the Mississippi but the smaller region bounded on the west by the Perdido River, the Suwannee River on the east, the Gulf of Mexico on the south, and the uncertain boundary with the United States on the north. Pensacola and San Marcos are two principal settlements, and this area approximates the western panhandle of the present-day state of Florida. When Spain acquired West Florida in 1783 the British boundary was the Apalachicola River, but Spain in 1785 moved it eastward to the the Suwanee River. (Few maps indicate this eastward shift.) The purpose of making the Suwannee River the eastern boundary was to transfer San Marcos and the province of Apalachee from East Florida to West Florida. After the 1795 Pinckney Treaty Spain and the United States agreed that the northern boundary was the thirty-first parallel west from the Chattahoochee River and the parallel intersecting the Flint and Chattahoochee rivers running eastward. Until after the Pinckney Treaty went into effect in the late 1790s, Spanish West Florida's northern boundary was indefinite. Spain regarded the Yazoo parallel, the Tennessee, Cumberland, or even Ohio rivers as the northern limit. This meant that for well over a decade Spain considered the western part of Georgia, the eastern part of Alabama, along with bits of Tennessee and North Carolina, as part of West Florida.