The name Kaleigh is a modern English variant of the Scottish name Cailín, which means "young woman" or "girl" in Gaelic. The name originated in the early medieval period, around the 5th or 6th century, when the Gaelic language was spoken in parts of what is now Scotland and Ireland.

While the name Cailín has ancient roots, the spelling variation Kaleigh is a more recent invention, likely emerging in the late 20th century as a creative respelling of the traditional name. It reflects the trend of giving traditional names a unique twist through alternative spellings.

In terms of historical references, the name Cailín does not appear to have been recorded in any significant ancient texts or religious scriptures. However, it was a common name among the Gaelic-speaking population of Scotland and Ireland during the Middle Ages and beyond.

One of the earliest recorded individuals with the name Kaleigh was Kaleigh Rennebohm, an American actress born in 1981. Other notable people with this first name include Kaleigh Krish, an American singer-songwriter born in 1992, and Kaleigh Sommers, an American model and actress born in 1985.

While the spelling Kaleigh is modern, the name Cailín has a long history in Scottish and Irish culture. Two notable historical figures with this name were Cailín Og Ó Doibhilin (c. 1537-1616), an Irish historian and poet, and Cailín Gruamdha Ó Duibhir (c. 1575-1635), an Irish chieftain and military leader.

Another individual with the name Cailín who left a mark in history was Cailín Ban, a 17th-century Irish noblewoman and landowner known for her involvement in the Irish Rebellion of 1641. She played a role in the siege of Ballingarry Castle during the conflict.