Since the early 20th century, the county's population has been shrinking.
As of the 2011 census, the county had 50,927 residents.
The population density is 9.5/km².

The Croatian State Bureau of Statistics estimated the population of the county to be 45,493 in 2017, and 45,184 in 2018.

Ethnic Croats are the majority.
They are 84.15% of the population.
Serbs are 13.65%.
Serbs are the majority in the municipalities of Vrhovine, Donji Lapac, and Udbina.

In 1991, before the Croatian War of Independence started, Croats were 59.7% of the population and Serbs were 37%.
The eastern part of the county was a majority Serbian area.
Since the early 20th century, the county's population has been shrinking. As of the 2011 census, the county had 50,927 residents. The population density is 9.5/km².
The Croatian State Bureau of Statistics estimated the population of the county to be 45,493 in 2017, and 45,184 in 2018.
Ethnic Croats are the majority. They are 84.15% of the population. Serbs are 13.65%. Serbs are the majority in the municipalities of Vrhovine, Donji Lapac, and Udbina.
In 1991, before the Croatian War of Independence started, Croats were 59.7% of the population and Serbs were 37%. The eastern part of the county was a majority Serbian area.
Lika-Senj County