The name of the lake goes back to the formerly common word for the mast intended as feed for cattle – the so-called Nonnen or Nunnen.

The pond and the nature reserve lie near Heubronn, a village in the parish of Neuenweg (in the municipality of Kleines Wiesental), in the Southern Black Forest in Baden-Württemberg.

On 1 March 1922 the rain-sodden bank could no longer resist the water pressure and the burst, destroying the riverbanks as far as the valley of the Little Wiese.

In 2004 the area hit the headlines when a number of environmentalists complained that tree felling had significantly changed the character of the cirque.

The conservation aim[5] is the preservation of the region as an especially beautifully formed cirque with high rock faces, the Nonnenmattweiher as a tarn with its moraine banks in front as a habitat for numerous rare and endangered animal and plant species.