Peder Mønsted - Parti fra Søkilde, med græssende køer ved søbredden - 1931

The experts at Bruun Rasmussen referred to the lake as "Søkilde Sø". They may know where that is - but it is not common knowledge shared on the internet. Mønsted only wrote "Søkilde", and this locality exists, among other places in central Jutland, situated at the lake Knudsø. That setting for the painting would be the guess of the uploader.