In Croatia, Hammer families are generally Croats (from Buzet area ), very rarely Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Drnis and Zagreb.
Prevalence
About 10 people with faimily name Hammer live in Croatia today, in 10 households. There were 0 of them in the middle of the past century, and their number multiplied. They are located and four other Croatian places, mostly in Zagreb (<10), Oprtalj in Buzet area (<5), Drnis (<5), Silo on the Island of Krk (<5), and in Rijeka (<5).
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.