Tarn Hows Tarn Hows, Lake District National Park, Ambleside, Cumbria LA22, United Kingdom 5 Natural scenery Introduction Houshu Lake is one of the few man-made lakes in the region, and it is now a habitat preferred by red squirrels. Address Tarn Hows, Lake District National Park, Ambleside, Cumbria LA22, United Kingdom Opening hours All day.