the lagoon was originally known as the piraguá, meaning cove of the fish ('pirá' fish and 'kûá'  cove),  and sacopenapã  (way of the herons) by the indigenous tamoios, who first inhabited the area.

by the sixteenth century, farmers had begun to inhabit the land, due to the suitability of its soil for planting sugar cane - at this time most of the smaller lakes and lagoons in the area were embanked to create space for the construction of buildings and plantations.

after being known by several other names throughout the early history of rio de janeiro, it was in the eighteenth century that the lagoon was finally named lagoa rodrigo de freitas, after a portuguese military officer, who owned much of the land around the lagoon.