The name Kiarra is a modern English variant of the Irish name Ciara, which is derived from the Gaelic word "ciar" meaning "black" or "dark-featured." The name has its roots in ancient Celtic culture and was initially popular among the Irish and Scottish people.

The earliest recorded use of the name Ciara dates back to the 7th century, when it was borne by an Irish saint, St. Ciara of Santiago de Compostela. She was a nun and abbess who lived in Spain and is venerated in the Roman Catholic Church.

In the 12th century, the name Ciara appeared in the Icelandic Saga of the Faroe Islanders, which recounts the history and settlement of the Faroe Islands by Norwegian and Celtic (Irish and Scottish) people.

One of the earliest known bearers of the name was Ciara Nic Dhàibhidh, a 16th-century Scottish noblewoman and chieftain of the Clan Davidson. She lived from around 1510 to 1585 and played a significant role in the clan's affairs during her lifetime.

Another notable figure was Ciara Maguire, an Irish chieftain who lived from 1590 to 1653. She was the daughter of Cuconnaught Maguire, the Lord of Fermanagh, and played a crucial role in the Irish Confederate Wars of the 1640s.

In the 18th century, the name was borne by Ciara Barry, an Irish poet and writer who was born in 1712 and died in 1801. She was known for her works in the Irish language and her contributions to the preservation of Irish literature and culture.

The modern spelling variant, Kiarra, emerged in the late 20th century and has become increasingly popular in English-speaking countries, particularly in the United States and Canada. It has been used as a first name for both girls and boys.