McCusker
An Irish surname meaning "son of Cuscair/Cusker," probably from an old personal name of uncertain meaning.
The #9,135 most common surname in the United States (2010 Census) — about 1 in every 86,387 Americans shares it.
Etymology
McCusker is an Anglicized form of the Gaelic patronymic Mac Cuscair, meaning "son of Cuscair." The second element is an old Irish personal name, usually treated as of uncertain origin, though it is sometimes linked to words associated with victory or success. As with many Irish surnames, the prefix Mac means "son of."
History
The surname is found in Ireland, especially in the north, and later spread through emigration to Britain, North America, and other English-speaking countries. In records it appears in several spellings, reflecting the difficulty of rendering Gaelic names in English. The name is usually associated with Irish families rather than a single universally traceable origin point.
Origin
Regions
Variant spellings
Fun fact
The spelling with Mc- is a later shorthand form; historically, Mac- was the fuller Gaelic-style prefix.