Boshkung is diamond-shaped with the two axes running roughly north-south and east-west. The longer north-south axis is about long and the east-west . The lake has a maximum known depth of 71 metres (233 feet). It is one of several lakes that make up the Gull River Watershed. One of three primary inflows is the
Gull River from Beech Lake on the east side of the lake. Other inflows are the Kennisis River over the Buttermilk Falls from Halls Lake at the north, and the Boshkung River over the Buck Slides Dam from Kushog Lake at the west. The primary outflow is the continuation of the Gull River and its extensive watershed system downstream through a narrows to Little Boshkung Lake at the south, whose waters eventually flow into
Balsam Lake and via the
Trent–Severn Waterway to
Lake Ontario. There is one named bay, Echo Bay, on the east side (formerly 'Loon Echo Bay'), south of the inflow of the Beech River. It also has a handful of small islands, two of which have seasonally occupied structures, at Echo Island in Echo Bay, and on one of the Gull Islands close to the lake's south end. Two Tree Island sits near the west shore. Boshkung experienced a reported 117 year high water event in the spring of 2013 pursuant to the Ontario Ministry of Natural Resources historical data. This flooding, including damages, impacted a wide range of lakes and communities in the Gull River and other watershed regions. ==History==