The Zastko surname seems have originated in Germany or perhaps Austria, although deep testing to date seems to indicate a rare, ancient Y-DNA lineage, with likely Asian origins.
As far back as at least the mid 1700's, Zastkos lived in what is today Slovenská Ves a village and municipality in Kežmarok District in the Prešov Region of north Slovakia at the foot of the Carpathian Mountains as well as surrounding villages/towns where Zastkos live to this day.

Related Zastko family members are currently known to reside in France, Italy, Slovakia and throughout the United States of America.