In Croatia, Kogej families are predominantly Croats (from Labin area ), rarely Slovenes (from Slovenia ), and barely Bosniaks (from Rijeka ). In the past century, relatively most of Croatian residents bearing this family name were born in Pula and Rijeka.
Prevalence
About 40 people with faimily name Kogej live in Croatia today, in 20 households. There were 20 of them in the middle of the past century, and their number doubled. They are located in 6 Croatian counties, in 6 cities and 6 other places, mostly in Zagreb (20), Pula (<10), Rijeka (<5), Rasa in Labin area (<5), and in Kastav (<5).
Outside Croatia
Family name Kogej (including: Koghee , Kogey and Kogei ) is present in 18 countries worldwide. "Kogei " is used by small number of 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 1902 in source Hartmann's General List of Apartments in Zagreb.