Final answer:
West Florida's borders fluctuated but generally were bounded by the Apalachicola or Suwannee Rivers to the east, the Mississippi River to the west, 31st parallel north to the north, and the Gulf of Mexico to the south. The U.S. seized the region during the War of 1812, and the Adams-Onís Treaty in 1819 formalized its acquisition by the U.S.
Step-by-step explanation:
The borders of West Florida in 1767 were not specifically defined in that year, as West Florida's boundaries were fluid and contested throughout its history. Nevertheless, in general terms, West Florida was created as a result of the 1763 Treaty of Paris when Britain gained control of Florida from Spain after the Seven Years' War. Its eastern border was often the Apalachicola River or the Suwannee River, its western limit reached to the Mississippi River, the north bordered by the 31st parallel north, and the Gulf of Mexico to the south. The complex history of the region, including conflicts such as the War of Jenkins' Ear and the desire to quell Native American tribes and runaway slave communities, shaped the geopolitics of the Floridas and surrounding colonies.
During the War of 1812, the American government, which had always had designs on Spanish Florida, managed to seize the panhandle region known as West Florida. The Adams-Onís Treaty of 1819, which resulted from geopolitical tensions including Andrew Jackson's unauthorized military incursion into Spanish East Florida, formalized the U.S. acquisition of Florida as well as delineated new boundaries for U.S. and Spanish territories in North America.