Macaulay, Macauley, MacAulay, McAulay and McAuley are surnames of Irish origin originating in Westmeath, Leinster anglicized from Irish Mac Amhalghaidh in the English language.
Some of the Irish Macaulay's settled in Scotland during the reign of Robert the Bruce.
[6] The Gaelic surnames originated as a patronyms, however they no longer refer to the actual names of the bearer's father's.
[6] In other cases, the surnames are derived from the Scottish Gaelic MacAmhlaibh or MacAmhlaidh,[4] or the Irish Mac Amhlaoibh.
[10] The table below shows data concerning racial-ethnic aspects of the surnames in the 2000 United States census (note that two fields have been suppressed by the United States Census Bureau for confidentiality reasons, since "MCAULAY" had fewer than 1,000 people).