Beira Interior Sul is a former NUTS3 subregion of Portugal integrating the NUTS2 Centro Region. It was abolished at the January 2015 NUTS 3 revision. It was bordered to the east and south by Spain, to the north by the Cova da Beira and Beira Interior Norte subregions and to the west by the Pinhal Interior Sul subregion. It was created around the city of Castelo Branco.
The main economic activity is agriculture and some related light industry. In its borders lies the International Tagus Natural Park that is one of the least densely populated areas in Portugal.
Wikipedia https://en.wikipedia.org/wiki/Beira_Interior_Sul
Coordinates 39°54'3.85" N -7°18'18.251" E