Complex sentence: Formerly part of the First Division, which included Kuching, it became a separate Division on 24 July 1986, with a total area of 4,967.4 square kilometres.
Split into simpler sentences: Formerly part of the First Division, which included Kuching, it became a separate Division on 24 July 1986. Samarahan Division has a total area of 4,967.4 square kilometres.