In Croatia, Biršić families are Croats (from Duga Resa ). In the past century, relatively most of Croatian residents bearing this family name were born in Duga Resa and Zagreb. In Galović Selo in Duga Resa every eighth inhabitant had the family name Biršić.
Prevalence
About 30 people with faimily name Biršić live in Croatia today, in 11 households. There were 20 of them in the middle of the past century, and their number increased by 30 percent. They are located in four Croatian counties, four cities and four other places, mostly in Ivanic-Grad (<10), Galovic Selo (<10), Koprivnica (<10), Belavici (<10), and in Graberje Ivanicko (<5).
Outside Croatia
Family name Biršić is present in three countries on two continents. The family name "Birsic " is used by some 100 people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.