The Mama lighthouse is located in the Carnaxide Sierra of the municipality of Oeiras, in Lisbon District, Portugal. It is built on a round hill, known as the Mama Sul, next to a Geodesic landmark. The Mama Lighthouse is about 4 km inland, northwest of Belém, and combines with the Esteiro and Gibalta lighthouses to indicate the alignment of the southern entrance to the Port of Lisbon.