The hydrographic slopes adjacent to the Tonnerre River are:

• North side: Coquille River, Coquille Lake, Boisvert River (Normandin River), Armitage River;
• East side: Chaudière River (Normandin River), Atouk Creek, Little Chef's River;
• South side: Bouteville Creek, Normandin River, Poutrincourt Lake, Marquette River West;
• West side: Nicabau Lake, Rohault Lake, Bouteroue Lake, Boisvert River (Normandin River).

The Tonnerre River originates at the mouth of "Île Ronde Lake" (length: 2.8 kilometres (1.7 mi) width: 0.5 kilometres (0.31 mi) altitude: 406 metres (1,332 ft)) in the township of Ducharme. The mouth of this head lake is located at:

• 5.2 kilometres (3.2 mi) north-east of Nicabau Lake;
• 9.1 kilometres (5.7 mi) north of the mouth of the "Tonnerre River" (confluence with the Normandin River);
• 23.4 kilometres (14.5 mi) south-east of Obatogamau Lakes;
• 32.1 kilometres (19.9 mi) northwest of the mouth of the Normandin River (confluence with Ashuapmushuan Lake);
• 152.8 kilometres (94.9 mi) northwest of the mouth of the Ashuapmushuan River (confluence with Lac Saint-Jean).

From the mouth of Round Island Lake, the "Tonnerre River" flows over 12.6 kilometres (7.8 mi), according to the following segments:

• 2.3 kilometres (1.4 mi) towards the Southwest, to the dump (coming from the North-West) of the Crouton lakes, the Pooh, the Bannock, Astier and Carei;
• 2.7 kilometres (1.7 mi) southeasterly to the outlet (from the southeast) of Wilfrid Lake;
• 2.8 kilometres (1.7 mi) southwesterly to route 167;
• 2.1 kilometres (1.3 mi) south by cutting the Canadian National Railway, then crossing Harquail Lake (length: 2.3 kilometres (1.4 mi); altitude: 392 metres (1,286 ft)), to its mouth;
• 2.7 kilometres (1.7 mi) southerly crossing Verreault Lake (elevation: 389 kilometres (242 mi)) along its entire length to its mouth. Note: This lake is also fed by the outlet (coming from the North-East) of Jacques-Drouin, Guitare and Hassels lakes.^[2]

The confluence of the "Tonnerre River" with the Normandin River is located at:

• 1.0 kilometre (0.62 mi) downstream north-east of the mouth of Nicabau Lake which is crossed by the Normandin River;
• 26.0 kilometres (16.2 mi) south-west of the mouth of the Normandin River (confluence with Ashuapmushuan Lake);
• 147.8 kilometres (91.8 mi) west of the mouth of the Ashuapmushuan River (confluence with the lac Saint-Jean);
• 186.7 kilometres (116.0 mi) northwest of the mouth of lac Saint-Jean (confluence with the Saguenay River).

The Tonnerre River flows into a small bay on the north shore of the Normandin River, downstream of the dam at the mouth of Nicabau Lake. From there, the current flows south-east along the Normandin River on 38.7 kilometres (24.0 mi) to the northwestern shore of Ashuapmushuan Lake. Then, the current takes the course of the Ashuapmushuan River which flows to Saint-Félicien, Quebec on the west shore of Lac Saint-Jean.

• Saguenay River
• Lac Saint-Jean, a body of water
• Ashuapmushuan River, a watercourse
• Ashuapmushuan Lake, a body of water
• Normandin River, a watercourse
• Lac-Ashuapmushuan, Quebec, an unorganized territory
• Le Domaine-du-Roy, a regional county municipality (MRC)
• List of rivers of Quebec