The Shire of Irwin is a local government area in the Mid West region of Western Australia, about 50 kilometres (30 mi) south of Geraldton and about 360 kilometres (220 mi) north of the state capital, Perth.

The Shire covers an area of 2,374 square kilometres (917 sq mi), and its seat of government is the town of Dongara.

The Irwin Road District was created on 24 January 1871 as one of the first regional local government areas in Western Australia.

In 16 June 1916, Irwin received a large land area from the Upper Irwin Road Board shortly before that entity's dissolution.

[3] The Shire is divided into four wards: The towns and localities of the Shire of Irwin with population and size figures based on the most recent Australian census:[4][5] As of 2023, 157 places are heritage-listed in the Shire of Irwin,[19] of which 16 are on the State Register of Heritage Places.