Lagoa (Portuguese for lagoon) is a municipality in the southwestern part of São Miguel Island in the Azores. The population in 2011 was 14,442. Lagoa is located east of Ponta Delgada, the island capital.

The municipality is located on the southern coast of São Miguel, and nestled between the three larger municipalities of Ponta Delgada (to the west), Ribeira Grande (in the north) and Vila Franca do Campo (on the eastern frontier); its municipal seat is approximately nine kilometers from the principal city on the island (Ponta Delgada). It was created on April 11, 1522 by royal decree from King D. João III, and although the municipal seat was temporarily assigned to Água de Pau, it is currently occupied by the urbanized core of Nossa Senhora do Rosário and Santa Cruz.

Its small territory is relatively rich in biodiversity, influenced by its differentiated environmental characteristics between the Fogo volcano (the Serra de Água de Pau) and the volcanic complex of Picos. Most of this space is occupied by pasturelands, cultivated tracts and, along the coast, an urbanized core. The cryptomeria, acacia and eucalyptus are just some of the variety of trees that populate the forests in the interior, while along the southern flank of Fogo, there are many endemic species of Erica azorica, Calluna vulgaris, the cedro-do-mato (Juniperus oxicedrus) the pau branco (Picconia azorica).

Ecoregions & protected areas:

• Ponta da Galera - with an area of 220 ha (195 ha coast), the 7180 meter long coastal habitat has been designated under the Rede Natura 2000 designation (Code PTMIG0020) as a protected habitat, due to its number of shallow bays and coves, endemic vegetation, marine environments and species of flora and fauna. In addition to the Azorean heather (Erica azorica) and carnations (Spergularia azorica), the area is known as a home for pods of Harbour porpoise (Phocoena phocoena), Common bottlenose dolphin (Tursiops truncatus), the Loggerhead sea turtle (Caretta caretta), as well as avian species of shearwaters (Calonectris diomedea boreallis) and Sterna.