Recorded in over forty spellings including Cowitz, Cowx, Kofax, Kovac, Kovalsky, Kovel, Kowal, Kowatsch, Kowalski, Kowalinski, Kovanko, Kowalczyk, and many others, this is a surname of Polish or perhaps in some cases, Russian origins.
It is or was, in its many and different native forms, recorded in other such varied places as The Ukraine, Germany, Belorussia, the Czech Republic, Slovakia, Croatia and Hungary. It can be ethnically either Christian or sometimes Jewish.
The origination is from the pre 7th century word 'kowac' meaning to forge, and hence is an occupational name for a smith, or at least an ironworker. However the additive suffix '-ski' when recorded, implies land and estate ownership, and like the German 'von' can also be a locational or status name for a person who came from one of the various places called Kowal.
Heraldically the surname has many coat of arms. Perhaps the most famous and the one associated with the famous Crusades to the Holy Land in the 12th century has the following blazon. A red field charged with a broadsword point down between two Turkish crescents, all gold. The blazon implies a glorious victory over the Muslims, although historically this is at best arguable.