Grasmere is one of the smaller lakes of the English Lake District, in the county of Cumbria. It gives its name to the village of Grasmere, famously associated with the poet William Wordsworth, which lies immediately to the north of the lake.
The lake is 1680 yd (1540 m) long and 700 yd (640 m) wide, covering an area of 0.24 mi² (0.62 km²). It has a maximum depth of 70 ft (21m) and an elevation above sea level of 208 ft (62 m). The lake is both fed and drained by the River Rothay, which flows through the village before entering the lake, and then exits downstream into nearby Rydal Water, beyond which it continues into Windermere.
The waters of the lake are leased by the Lowther Estate to the National Trust. The waters are navigable, with private boats allowed and rowing boats for hire, but powered boats are prohibited. The lake contains a single island, known as The Island.