The Municipality of Newcastle was a local government area in the Wheatbelt region of Western Australia, about 85 kilometres (53 mi) north-east of Perth.

Its first election was held on Monday 19 November 1877, at which Charles Samuel Monger won 26 votes against Arthur Wroth's 20 to become the first chairman.

An observer writing in 1878 commented that the previously neglected streets had markedly improved in their condition.

The council's small revenue, which could not easily increase due to the amount of non-rateable Government property and the failure to merge North Toodyay into the municipality, was outstripped by the cost of administration.

By 1911, the council had £50 to spend on roads, and was seeking from the state government £350 to improve Stirling Terrace and £250 for the town hall.