One Mile Creek is located within the Town of Niagara-on-the-Lake (NOTL) with its outlet about 1.6 kilometres (1 mile) to the west of where the Niagara River flows into Lake Ontario. Following the gentle natural contours of the land, One Mile Creek meanders through the Old Town neighbourhoods before pooling in Landsdowne Pond to reach the outlet to Lake Ontario.
The watershed is relatively small, with a drainage area to the creek outlet being approximately 5.2 square kilometres. The creek drains a highly urbanized watershed area and flows through mostly private property.
The construction of the Epps Drain upstream of John Street diverts a large portion of the headwater flows (about 30% of the drainage area) easterly to the Niagara River. Major event flows (near the regional flood flow) overflow the Epps Drain and spill into One Mile Creek.
The William Street Pumping Station was constructed to convey flows from a portion of NOTL served by combined sewers, to the regional Water Pollution Control Plant. As of 2009, there are no more combined sewers in NOTL.