Twelve Mile Creek is a waterway located on the Niagara Peninsula in the Regional Municipality of Niagara in Southern Ontario, Canada. Its headwaters are located in the town of Pelham, encompassing some of the most unspoiled and natural areas of Niagara area. The creek's lower reaches flow through urban areas of Thorold and St. Catharines and has been heavily altered by human activity for almost two centuries. The creek was first known as "Ashquasing" by the Mississaugas Indigenous people, the name meaning "that which lies at the end" in the Anishinaabe language.