Buade Lake is located at the western end of the MRC Le Domaine-du-Roy. This lake has a length of 22.9 kilometres (14.2 mi), a maximum width of 2.0 kilometres (1.2 mi) and an altitude of 392 metres (1,286 ft). The northern part of the lake has an archipelago of islands. This lake constitutes a large widening of the Normandin River which crosses it on its full length.

The mouth of Lake Buade is located at:

• 4.6 kilometres (2.9 mi) south of the confluence of the Normandin River with Poutrincourt Lake;
• 9.5 kilometres (5.9 mi) south of the mouth of Poutrincourt Lake;
• 24.2 kilometres (15.0 mi) south of the mouth of Nicabau Lake, which is crossed by the Normandin River;
• 28.7 kilometres (17.8 mi) south-west of the mouth of the Normandin River;
• 144 kilometres (89 mi) west of the mouth of the Ashuapmushuan River (confluence with lac Saint-Jean.[1]

The main hydrographic slopes adjacent to Buade Lake are:

• North side: Poutrincourt Lake, Normandin River, Bouteroue Creek, Bouteroue Lake, Rohault Lake, Nicabau Lake, Obatogamau Lakes;
• East side: Poutrincourt Lake, Du Milieu River (Poutrincourt Lake), Marquette River West, Marquette River, Ashuapmushuan Lake;
• South side: Normandin River, Little Buade Lake, Townsend Creek, Du Milieu River (Poutrincourt Lake), Marquette River;
• West side: Titipiti River, Ventadour Lake (Ventadour River), Ventadour River, Queue de Castor River, Cawcot River.

From the road bridge at the mouth of lake Buade Lake, the current flows over:

• 5.4 kilometres (3.4 mi) to the North by making a hook of 1.2 kilometres (0.75 mi) to the East, to it confluences with the Poutrincourt Lake;
• 5.8 kilometres (3.6 mi) to the North crossing the Poutrincourt Lake;
• 15.6 kilometres (9.7 mi) north, forming a hook to the east, to a bay south of Nicabau Lake, the southern part of which is crossed by the Normandin River. From there, the Normandin River flows southeast to Ashuapmushuan Lake which is the head lake of the Ashuapmushuan River.

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