Weldon Spring Conservation Area

Weldon Spring Ordnance Works (WSOW) was a 17,323-acre (70.10 km2) U.S. Government-owned, contractor-operated (GOCO) facility in St. Charles County, Missouri, 55 km west of St. Louis. The site was originally operated by the Atlas Powder Company during World War II from 1941 to 1945 to produce explosives. The Atomic Energy Commission acquired part of the property in 1955, and Mallinckrodt, Inc. processed uranium ore from 1957 to 1966 under contract. The site has been divided into several parcels, and ownership has transferred over the years. Two portions of the original WSOW property are now Superfund sites that require substantial cleanup efforts. The environmental remediation of the WSOW site is currently designated as a major project of the Defense Environmental Restoration Program of the United States Department of Defense. Part of the original property is still used by the Army Reserve as the Weldon Spring Training Area.

Mechanicsville is an unincorporated community in St. Charles County, in the U.S. state of Missouri.

Hamburg was a small town in St. Charles County, Missouri, United States. Hamburg was one of three towns, along with nearby Howell and Toonerville, that were evacuated and terminated in 1940–1941 when the area was taken over by the United States Department of the Army for the Weldon Spring Ordnance Works, which manufactured trinitrotoluene (TNT) and dinitrotoluene (DNT) and later processed uranium.

Wolf-Ruebeling House was a historic home near Defiance, St. Charles County, Missouri. It was built between about 1857 and 1859, and was a two-story, vernacular style brick I-house with Classical Revival style design references.: 2–3  It was destroyed in a 1985 fire.It was added to the National Register of Historic Places in 1983 and delisted in 1994.

Toonerville is an unincorporated community in St. Charles County, in the U.S. state of Missouri.

Femme Osage Creek is a stream in St. Charles County in the U.S. state of Missouri. It is a tributary of the Missouri River.The stream headwaters arise just west of Missouri Route T and the stream flows initially west then turns north past the Femme Osage community on route T then turns to the east. The stream flows parallel to Missouri Route F past the Daniel Boone Home north of Schluersburg. It flows under Missouri Route 94 north of Defiance and enters the Missouri just south of the community of Hamburg within the Weldon Springs Conservation Area.Femme Osage is a name derived from French meaning "Osage woman". It is unclear why the name Femme Osage was applied to this stream. Many variant names have been recorded, including "Faim of the Hoozaw River", "Femme Osage River", "Osage Womans River", and "Wife of Osage River".

Defiance is an unincorporated community and census-designated place in Saint Charles County, Missouri, United States. As of the 2020 census, the population was 159.

August A. Busch Memorial Conservation Area is a 6,987-acre (28.28 km2) conservation area that is owned and managed by the Missouri Department of Conservation. Located in St. Charles County, Missouri, the land was purchased by the Department of Conservation with help from Alice Busch, the wife of August Anheuser Busch, Sr., in 1947 from the U.S. Government.

Isaac McCormick House, also known as McCormick Farm, is a historic home located near Defiance, St. Charles County, Missouri. It was built about 1867, and is a two-story, "L"-plan, log dwelling. It consists of a single pen hewn log main section with single pen hewn log ell. The main section measures approximately 18 feet wide and 27 feet deep and has a side gable roof.: 5 It was added to the National Register of Historic Places in 2004.

Callaway Fork is a stream in the U.S. state of Missouri. It is a tributary of Femme Osage Creek. Callaway Fork has the name of Flanders Callaway, a pioneer settler.