Miramichi Inner Bay is a large, shallow estuary forming part of Miramichi Bay on the Gulf of St. Lawrence in New Brunswick. It is separated from the outer bay by a line of uninhabited barrier islands, including Portage Island, which provide some protection from ocean storms. The bay is a drowned river valley, featuring the flooded, meandering ancient channel of the Miramichi River, which serves as a navigable route for ships. The inner bay is triangular in shape and extensive, with the overall Miramichi Bay system covering a surface area greater than 300 square kilometers. The inner bay itself averages only 4 meters in depth, with the navigation channel ranging from 6 to 10 meters deep. The environment is highly dynamic, subject to significant freshwater outflow during the spring freshet, rising saltwater content in summer, fall storms that reshape the islands and channels, and complete encasement by winter sea ice. The shallow waters warm rapidly during the summer. For paddlers, this indicates a saltwater environment with significant tidal influence and exposure to wind and weather from the Gulf, particularly where unprotected by the barrier islands. The presence of a shipping channel necessitates awareness of boat traffic when crossing or paddling near the navigable route. The uninhabited barrier islands and the historic, meandering channel are notable geographical features.