Beside the foot of Äsåsen lies the small lake Äs puss. Take a break at the fine rest area and look out over the open water and bird life. Härnevi Hembygdsförening has done a good job of restoring the lake, which was about to grow again.
The lake is almost completely round and a handy memory of the ice age. Äsåsen is a pebble rock formed by the inland ice floods. An iceberg was embedded among the deposits of the ridge, when the ice melted late in the sides, a large crater was filled with water, ie Äs puss.