Blay Creek

Blay Creek is a stream in St. Francois and Washington counties in the U.S. state of Missouri. It is a tributary of the Big River.

The stream source area is east of Summit in eastern Washington County and it flows to the southeast roughly parallel to Missouri Route 8. The stream enters the Big River just after entering St. Francois County. The confluence is about three miles (five kilometers) west of Leadwood.

The stream headwaters are at 37.91278°N, -90.69611°W and its confluence with the Big River is at 37.87°N, -90.63889°W.

A variant name was "Blays Creek". The stream most likely has the name of a pioneer citizen, possibly that of Joseph Blay.