São Nicolau has a population of 12817 inhabitants (2010 census), concentrated in the two main towns of Ribeira Brava and Tarrafal (also the centres of the two municipal districts). However, many hamlets are dotted along the north flank (Ribeira da Prata, Fajã de Cima y Fajã de Baixo, Cachaço, Juncalinho, etc.), while the south sector is less populated, except for Tarrafal. Population numbers changed little in the 1960s, varying between 13000 and 16300. However, numbers have gradually dwindled from the 1970s onwards. This is largely due to emigration and inter-island migration, such as to Sal and Boavista, for better employment opportunities.
Economic activity continues to depend on the primary sector (agriculture, stockbreeding and fishing), although tourism is slowly on the rise, albeit currently limited to hikers, and visitors seeking contact with nature and local people. The only hotel and guesthouse facilities are in Ribeira Brava and Tarrafal, which are linked by a modern road. Irrigated agriculture (e.g., sugar cane for making grogue or aguardiente) continues to thrive, partly thanks to a water tunnel excavated in Fajã valley and the fishing sector is locally well-developed, with a large fleet in Tarrafal and smaller fleets at several spots around the coasts, such as Preguiça.
Livestock numbers are high (especially goats, sheep and donkeys) and many areas are still given over to grazing, particularly the green pastures that appear after the summer and autumn rains. However, grazing continues in mountainous areas at other times of the year. Industry on São Nicolau has always been minimal, but has included fish processing (canned tuna in oil), grogue or aguardiente production, and small whaling stations in the late 19th and early 20th centuries near Carriçal and in Tarrafal, where up to ten people were employed at one point. Considerable efforts have been made in the last thirty years to reforest several areas of the island (e.g., Carriçal, Monte Gordo), and there are now around 2000 ha of woodland.