This lake has a length of 16.7 kilometres (10.4
mi), a maximum width of 5.1 kilometres (3.2
mi) and an altitude of 365 metres (1,198
ft). Caopatina Lake has many bays, peninsulas and islands. Six narrow, long peninsulas depart from the north shore stretching southwest to the center of the lake, the longest of which is 4.6 kilometres (2.9
mi). The lake has an archipelago of islands in the Southeast. The Caopatina River (tributary of the Waswanipi River) crosses the north-eastern part of Caopatina Lake to the west.
Lake Caopatina gets its supply on the east side by the Opawica River, on the south side by the Roy River and on the west side by the discharge of a group of small lakes.
The mouth of this lake Caopatina is located at the bottom of a bay in the North-West at:
- 3.9 kilometres (2.4 mi) east of Des Vents Lake (Opawica River);
- 155.2 kilometres (96.4 mi) south-west of downtown Chibougamau;
- 34.4 kilometres (21.4 mi) south-east of the village center of Chapais, Quebec;
- 87.2 kilometres (54.2 mi) east of the village center of Waswanipi;
- 75.3 kilometres (46.8 mi) north of Gouin Reservoir;
- 170 kilometres (110 mi) north-east of Lebel-sur-Quévillon.[1]
The main hydrographic slopes near Lake Caopatina are:
- North side: Irene River, Fancamp Lake, Chibougamau River, Chibougamau Lake;
- East side: Opawica River, Eu Lake, Nemenjiche Lake, Rohault Lake;
- South side: Roy River (Opawica River), Surprise Lake (Roy River), Cawcot River;
- West side: Des Vents Lake (Opawica River), Opawica River, Doda Lake.