Kelsey is an English given name with origins dating back to the Middle Ages. It is derived from the Old English words "ċel" meaning "brook" or "chalky stream" and "ēg" meaning "island" or "dry ground." The name was originally a surname referring to someone who lived near a chalky stream or on dry ground near a stream.

The name Kelsey first appeared in historical records in the 12th century, particularly in areas of England such as Lincolnshire and Yorkshire. It was initially used as a locational surname, but over time, it transitioned into a given name.

One of the earliest documented instances of Kelsey as a first name dates back to the 14th century, with a reference to a man named Kelsey of Bramham in Yorkshire, England, in the year 1379.

In the 15th century, a notable figure named Kelsey Whetstone was recorded as a member of the English gentry in Hertfordshire. Whetstone was a prominent family name during that era, and the combination of Kelsey and Whetstone suggests that the name Kelsey held some significance among the gentry.

During the 16th century, a man named Kelsey Throckmorton was a member of the English landed gentry and served as a member of parliament for Worcestershire in 1553. Throckmorton was a prominent surname in English history, and the use of Kelsey as a given name within this family further solidified its importance.

In the 17th century, a woman named Kelsey Rayner was born in Gloucestershire, England, in 1642. Rayner was a respected family name in the region, and the inclusion of Kelsey as a given name for a female suggests that it had become more widely accepted for both genders by that time.

Another notable figure from history bearing the name Kelsey was Kelsey Jones, born in 1785 in Wales. Jones was a Welsh poet and writer who gained recognition for his works in the early 19th century, further cementing the name's association with literary and artistic circles.