Grmoja families are Croats and they are mostly from Vrgorac area. In the past century, relatively most of Croatian residents bearing this family name were born in Metkovic and in Vrgorac area. In Dubrave in Vrgorac area every sixth inhabitant had the family name Grmoja.
Prevalence
About 150 people with faimily name Grmoja live in Croatia today, in 70 households. There were 80 of them in the middle of the past century, and their number increased by 80 percent. They are located in 6 Croatian counties, in 11 cities and 8 other places, mostly in Metkovic (65), Kobiljaca in Vrgorac area (25), Zagreb (15), Makarska (15), and in Donji Miholjac (10).
Outside Croatia
Family name Grmoja is present in four countries on three continents. The family name "Grmoja " 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 2007 in source Encyclopaedia of Croatian Surnames.