Fort Zumwalt Park is an historic site within O’Fallon in St. Charles County, in the US state of Missouri. The fort dates back to the pioneer era in the early 19th century, shortly after the Louisiana Purchase, and was the fortification of the Zumwalt Family. In 1798 Jacob Zumwalt (1752–1820), a Revolutionary War veteran, settled on the spot. With the outbreak of the War of 1812 and increasing Indian problems, the Zumwalt's home was enlarged, portholes were added and the compound was enclosed within a stockade fence. It became the fortified gathering place for area settlers during times of Indian uprisings. It is said that the Zumwalt home was the first hewn-log house built on the west side of the Mississippi River. The first Methodist Sacrament in Missouri was said to have been celebrated in the Zumwalt home in 1807. The land was sold in 1837 to Major Nathan Heald. The land was purchased by the state of Missouri in the early 20th century, and became Fort Zumwalt State Park.