It attained municipal status in 1949. The name of the town translates in both the Khoekhoe and Khoemana languages. The first translation from Khoekhoe means "large eye". At the Roman Catholic Mission Station in the town there is a natural water fountain called Big Eye or Keimoes. The "big eye" may also come from the vast views that can be seen from the Tierberg, a small mountain outside the town. The second translation is taken from the Khoemana language. The town is said to have gotten the name in the 1860s from Klaas Lukas, a Khoemana leader  Klaas Lukas called it Keimoes (‘mouse nest’) after the colonies of mice living there.
The discovery of Middle Stone Age stone tools such as, blades, points, scrapers and one adze found in Keimoes confirms the prehistoric activity in the town. An irrigation system was built in 1882 and in 1883 a second furrow was added to the system. These furrows contributed to the advancement of the town and in the following years many families started moving to the area. In 1887 a school was opened, with Pieter Rossouw as its first teacher. The school was closed again in 1899, due to the start of the South African War or second Anglo-Boer War. By 1910, Keimoes had its own hotel, prison, court and police service. In 1951, Keimoes opened its own power station and the town was powered by electricity.