The survey of Arran Township was completed in 1851, after the first settler(s) arrived around 1850. Lands opened for official occupation in July 1852.
In 1853, when the United Townships of the County of Bruce was dissolved, Arran Township became the senior township in the municipality of the United Townships of Arran and Elderslie.
Two years later, that union dissolved and Arran Township existed as an independent municipality in 1856.
In 1857, Amabel Township, to the north, united with Arran Township. In 1858, Albemarle Township also joined the union. The three townships remained united, with Arran Township as the senior township, until January 1, 1861 when Arran Township separated to become, and remain, an independent township until 1999.
Within the geographical area of Arran Township, the community of Tara grew in population and incorporated as a Village on January 1, 1881.
In January 1999, Arran Township, Tara, Elderslie Township, Chesley, and Paisley amalgamated to form the Municipality of Arran-Elderslie in January 1999.
Robertson, Norman. “The History of the County of Bruce and of the minor municipalities therein.” Toronto: William Briggs, 1906.