The hydrographic slope of lake Rocher is accessible via the forest road R1023 (east-west) from the west, passing north of “Île au Pain de Sucre”, then heading north-east to pass from the West of lake Rocher; the R1023 connects the "James Bay Road" (North-South direction) that comes from Matagami.

The surface of Lake Rocher is usually frozen from early November to mid-May, however, safe ice circulation is generally from mid-November to mid-April.

Made long by the widening of the Nipukatasi River, this lake has 17 islands and a few bays.

The surrounding areas near the lake have a generally leveled topography, except Mount Dome whose summit culminates at 381 metres (1,250 ft) at 3.6 kilometres (2.2 mi) north-west of the lake.

This summit is equidistant from Quénonisca Lake, which is a neighboring body of water to the northwest.