Lilla Karlsö is a small
Swedish island in the
Baltic Sea, situated about west of
Gotland and from
Stora Karlsö. It has an area of about and is high. Most of the island consists of a
limestone plateau. Parts of the shoreline is bordered by steep cliffs. The island is mostly covered by
alvar. There is also some very old broadleaf forest, which is unique for Gotland. There are several caves and up to high limestone pillars.