San Juan is subdivided into 18 districts (barrios), 16 of which fall within the former (until 1951) municipio of Rio Piedras. 8 “barrios” are further subdivided in to “sub-barrios”, including both “barrios” of the former municipio of San Juan:
Former municipio of Río Piedras
Caimito
Cupey (formerly two “barrios”: Cupey Alto and Cupey Bajo)