Lake Hornborga (Swedish: Hornborgasjön) is a lake in Västergötland in Sweden, famous for its many birds, in particular the many cranes that stay here temporarily during their annual migrations.

Lake Hornborga was created after the last ice age, approximately 10,000 years ago.

In order to relieve starvation, it was decided in 1802 to lower the water level in order to create pastures for cattle to graze.

The surface area was reduced from 28 km2 to less than 4 km2, but rather than make way for pastures, reeds took over and turned the lake into a swamp.

In 1965, a Government investigation suggested that the lake be restored, and between 1992 and 1995, the water level increased by an average of 0.9 metres.