Rotopōhueroa / Lake Constance is a stunning alpine lake nestled within Nelson Lakes National Park on the South Island of New Zealand. Sitting at an elevation of 1,340 metres in a vast post-glacial basin, it holds the distinction of being the largest alpine lake in New Zealand, stretching approximately two kilometres in length and 700 metres at its widest point. Flanked by dramatic mountain terrain, the lake drains not through a surface outlet but via an underground river that feeds into the nearby Blue Lake (Rotomairewhenua). The lake's Māori name, Rotopōhueroa, was officially recognised in August 2014 following the Treaty of Waitangi settlement between the Crown and Ngāti Apa ki te Rā Tō. Its remote, high-country setting makes it one of the more adventurous fishing destinations in the Nelson region, rewarding those willing to make the journey with a truly spectacular backcountry experience.