Katthammarsvik is a small harbour settlement in the parish of Östergarn on the island of Gotland. It is located in Gotland Municipality, Gotland County. As of 2005, it was in statistical terms defined as a småort (small locality) and has formerly, very briefly, held the status of a tätort (locality).Katthammar has had a lime industry consisting of several kilns that flourished after Gotland came under Swedish rule in 1645.