Tantamar is a town on the mainland Principautés de Lhazaar. The town is situated on the coast of the Spring Harbor and north of the Whitespine Forest.
Maison Thuranni has an enclave in the town and is considered to be highly important as it is the hub that connects mainland Khorvaire to the Thuranni headquarters in Port Royal. Because of its position the enclave is the heart of Maison Thuranni's activities in Khorvaire. Thuranni has also constructed a grande theater in the town and the finest artists and actors from the Réseau de l'Ombre perform on this stage.