Complex sentence: During the late 18th century and early 19th century, the area was traversed by the Natchez Trace, on which a trading post stood before a treaty with the Choctaw, the Treaty of Doak's Stand in 1820, formally opened the area for non-native American settlers.
Split into simpler sentences: During the late 18th century and early 19th century, the area was traversed by the Natchez Trace and had a trading post. A treaty with the Choctaw, the Treaty of Doak's Stand in 1820, formally opened the area for non-Native American settlers.