Bachalpsee or Bachse is a lake with an area of 8.06 ha (19.9 acres) close to the First (a minor summit below the Schwarzhorn which can be reached with a cable car) and above Grindelwald in the Bernese Oberland (Bernese highlands) of Switzerland.

The lake, located at an elevation of 2,265 m (7,431 ft), is split by a natural dam, the smaller part of the lake being 6 m (20 ft) lower. The exact coordinates are 46°40’10″N 8°1’24″E and you can see it here on Google Maps.

According to Walking Switzerland there is a moderately difficult hike of 9 km (5.6 m) to the lake. With a total ascent of 260 meters (858 ft) and a total descent of 660 meters (2,178 ft), the hike is estimated to take about 3.25 hours.

It starts at the top station of the Grindelwald to First gondola lift and ends at a small restaurant at Bussalp. More info on the hike can be found here.