It included Methven, Mount Somers, and Lake Heron.
In the 1887 election, most of the electorate's southern half was taken away to join the new Rangitata seat, but in the 1890 election, most of this territory was regained, with a similar amount of territory in the north, around Methven, being taken instead.
The 1919 election saw a complete revocation of this, with the electorate going back to focus on its original southern territories, and gaining Lake Coleridge.
The 1941 New Zealand census had been postponed due to World War II, so the 1946 electoral redistribution had to take ten years of population growth and movements into account.
In the 1957 election, it gained Geraldine from Waimate, but lost Methven to Selwyn.
In the 1963 election, it gained a large amount of inland territory, including Lake Tekapo and Twizel.
In 1969 election, the electorate was abolished — most of its territory was merged with Waitaki to form South Canterbury, while Ashburton itself was incorporated into Selwyn.
The Liberal Party held the seat for a time during its period of dominance, but the seat later became the stronghold of William Nosworthy, a senior figure in the conservative Reform Party.