About 23 fish species have been identified in the Groundhog River, including self-sustaining population of lake sturgeon which are provincially rare to uncommon.[3]
The Groundhog River is an advanced-level canoe route with several series of rapids and white water, in particular from the north of Groundhog Lake to the town of Fauquier; however, this river trip can be extended all the way to James Bay via the Mattagami and Moose Rivers.[3]
The river continues north under Ontario Highway 101, passes over the Upper Falls and series of unnamed cataracts and enters Cochrane District at geographic Enid Township.[6] It continues north through the Flying Post 73 Indian Reserve,[6][7][8] part of the Flying Post First Nation, over unnamed cataracts, jogs west then again north over the course of the Six Mile Rapids and takes in the left tributary Ivanhoe River and right tributary Nat River. The Groundhog River again jogs west, takes in the left tributary Otapingshewee River, then heads north through the Ten Mile Rapids, passes over the Carmichael Falls Generating Station and dam[5][9] and takes in the left tributary Wakusimi River. It heads around Bremner Island, and reaches the community of Fauquier in the incorporated township of Fauquier-Strickland. It is crossed there by Ontario Highway 11 and by the Ontario Northland Railway secondary main line, formerly a Canadian National Railway secondary line and originally the National Transcontinental Railwaytranscontinental main line.
The river continues north around a series of small islands and the Dixon Rapids, Hamilton Rapids and La Duke Rapids, passes over the Whist Falls, and reaches its mouth at the Mattagami River in geographic Clay Township.[10] The Mattagami River flows via the Moose River to James Bay.
The Groundhog River Waterway Provincial Park is a waterway park that protects about 180 kilometres (110 mi) of the river and its banks in 2 non-contiguous sections, from the outlet of Groundhog Lake to MacVicar geographic township, and from 10 kilometres (6.2 mi) downstream of Fauquier to its mouth at the Mattagami River. In the future, additional lands may be added that will reduce or remove the gap between the 2 sections. It was established in 2006 and is meant for remote canoe camping for advanced canoeists, as well as fishing, hunting, and nature watching.[3][12]
Because of its length, the park features about 22 different landform vegetation combinations, of which weakly broken ground moraine and lacustrine deposits are the dominant types. Its vegetation is characterized by mixed conifer and mixed deciduous forests. It is a non-operating park, meaning that there are no facilities or services.[3][12]
