The official documents that formalise Brazilian defence policy delineate Brazil’s “strategic surroundings” as encompassing South America, the African South Atlantic countries, Antarctica, and the South Atlantic Ocean. However, beyond this geographical demarcation, the official documents lack a precise definition of the term. This chapter aims to discuss and clarify the concept of “Brazilian strategic surroundings,” contrasting it with the works of Brazilian geopoliticians associated with the Brazilian Superior War College (BSWC): Golbery do Couto e Silva, Therezinha de Castro, and Carlos Meira Mattos, particularly regarding Brazil’s role in the South Atlantic Ocean. We argue that these scholars have contributed to expanding the notion of Brazil’s area of interest, which is intrinsically linked to the perception that the country has the potential to become a great power. The chapter begins by presenting some of the fundamental principles that guided the creation of the BSWC and its relationship with the Brazilian Ministry of Foreign Affairs (MFA). It then summarises the ideas of Brazilian geopoliticians related to Brazil’s priority areas of interest, including the South Atlantic. Subsequently, the work examines the use of the term “Brazilian strategic surroundings” in Brazilian defence documents. Also explored are previous definitions of the term as coined by Brazilian academics and military officers, contrasted against concepts such as “sphere of influence” and “sphere of interest.” The ultimate contribution of this chapter is to clarify the origins and development of the term “Brazilian strategic surroundings” as used in Brazilian defence documents and to engage with existing definitions of the concept. The methodology relies on the analysis of primary sources, particularly Brazilian defence documents, and the discussion of scholarly materials on Brazilian geopolitics and defence policy.