SR2020 "Settlements" are the native Cities, Towns and Villages found on the game Map. They serve to house a region's population, to host industry and to generate supply for the region.
Settlements can act as "hubs" for non-military "Urban" production facilities such as Goods factories, Power Plants and other Urban support facilities. They can even host military Bases such as Barracks, Air Fields, Sea Piers and Fortifications. However they cannot host strictly Industrial facilities such as Timber Mills and Coal Mines, or strictly military facilities such as Fabs.
Settlements are intrinsic to the game's starting Map and cannot be created or destroyed. They can however be depopulated by warfare.