Electoral district of Collie-Preston

Collie-Preston Western Australia—Legislative Assembly
Location of Collie-Preston (dark green) in Western Australia
State	Western Australia
Dates current	1901–present
Namesake	Collie, Preston River
Electors	28,736 (2017)
Area	4,344 km2 (1,677.2 sq mi)
Demographic	South West

Collie-Preston is a Legislative Assembly electorate in the state of Western Australia. While the seat was known as Collie for just over a century of its existence as an electorate, the seat was known as South West Mining from 1901 to 1904, and Collie-Wellington from 2005 to 2008. It is named for the South West coal mining town of Collie. While historically a very safe seat for the Labor Party, redistributions in 1988 and 2007 due to increases in the quota for country seats which had historically been malapportioned resulted in the seat incorporating surrounding rural shires which were hostile to Labor and thereby becoming more marginal.

Collie was originally created as the seat of "South West Mining" in the Constitution Act Amendment Act 1899, the last redistribution of seats to require a modification of the Constitution. It was first contested at the 1901 election. In 1904, it was renamed "Collie" with almost no changes to its boundaries. In the Redistribution of Seats Act 1911, its boundaries were so unusually contorted by the then-Liberal government, which was accused of trying to lock Labor votes in Premier Frank Wilson's marginal seat of Sussex behind Collie's boundaries, that the Kalgoorlie Miner and other newspapers used the seat's map as an effective mascot for the bill. However, the boundaries remained unchanged until a later redistribution ahead of the 1930 election.