The Big Bottom massacre occurred on January 2, 1791, near present-day Stockport now in Morgan County, Ohio, United States. It is considered part of the Northwest Indian Wars, in which native Americans in the Ohio Country confronted American settlers, regular soldiers and militia, seeking to expel them from their territory.

Following the American Revolutionary War, the United States government was selling land in the Ohio Country, mostly to companies that promised to develop it. A group of squatters had moved up to this area and settled along flood plain, or "bottom" land, of the Muskingum River, some 30 mi (48 km) north of an Ohio Company of Associates settlement at Marietta, Ohio. The settlement was raided by Lenape and Wyandot warriors seeking to expel the interlopers. They stormed the incomplete blockhouse and killed eleven men, one woman, and two children. (Accounts vary as to the number of casualties.) The Native Americans captured three settlers, with at least one dying later, while four others escaped into the woods.

The Ohio Company of Associates sought to provide greater protection for settlers in the Northwest Territory, as the conflicts became more widespread. A coalition of Native American tribes fought to expel the newcomers and preserve their lands. The war did not end until 1794.

The Ohio History Connection manages the three-acre Big Bottom Park site, which has been listed on the National Register of Historic Places. In addition to the markers noted below, the site features a 12 ft (3.7 m)-tall marble obelisk, picnic tables, and information signs about the site's history.