Turtle Creek is a  tributary of the Monongahela River in Allegheny and Westmoreland counties in the U.S. state of Pennsylvania. At its juncture with the Monongahela is Braddock, Pennsylvania, where the Battle of the Monongahela ("Braddock's Defeat") was fought in 1755. In the mid-19th century, the Pennsylvania Railroad laid tracks along the stream as part of its Main Line from Philadelphia to Pittsburgh.