Machens is an extinct town in St. Charles County, in the U.S. state of Missouri. The GNIS classifies it as a populated place. The Katy Trail, a recreational rail trail, begins at Machens.
A post office called Machens was established in 1895, and remained in operation until 1956. The community most likely has the name of Andrew Machens, Sr.
Coordinates: 38°54′11″N 90°19′56″W / 38.90306°N 90.33222°W