According to the 2001 census, Primorsko-goranska County has 305,505 residents. With the share of 6.9% in the overall population of Croatia (4.437,000) it is the fifth largest County after the City of Zagreb (779,145), the Splitsko-dalmatinska County (463,677), the Osječko-baranjska County (330,506) and the Zagrebačka County (309,696)..

The City of Rijeka - seat of Primorsko-goranska County with 143,800 inhabitants is the third largest city in Croatia - after the city of Zagreb (691,724) and the city of Split (175,140).

The smallest town in Primorsko-goranska County is the town of Cres with 2959 inhabitants, while the smallest municipality is that of Brod Moravice with 985 inhabitants.