Kalamaja is a subdistrict of the district of Põhja-Tallinn in Tallinn, the capital of Estonia. It is located just northwest of the historical town centre, on the coast of the Tallinn Bay. Kalamaja has a population of 9,820.

Patarei Prison, also known as Patarei Sea Fortress and Tallinn Central Prison, commonly known as The Battery (Patarei), is a building complex in Kalamaja district of Tallinn, Estonia. The premises cover approximately four hectares of a former sea fortress and prison, located on the shore of Tallinn Bay.