The highest hill in Tallinn is a point located in Hiiu, in the Nõmme district, in the southwestern part of the city - its height is 64 m above sea level.

A limestone cliff runs through the town and can be seen at Toompea and Lasnamäe. This cliff forms the geological dividing line of the land on which Tallinn is located - an area formed in the Ordovician in the south and the Cambrian in the north.