Sinčić families are Croats and they are mostly from Kastav. In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and Pula. In Rubeši in Kastav every fourth inhabitant had the family name Sinčić.
Prevalence
About 340 people with faimily name Sinčić live in Croatia today, in 140 households. There were 420 of them in the middle of the past century, and their number decreased by 20 percent. They are located in 9 Croatian counties, in 20 cities and 27 other places, mostly in Skropeti in Pazin area (35), Pula (30), Umag (30), Rijeka (25), and in Kastav (25).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.