Ridgewood's name refers to the wooded terrain on the Swan Coastal Plain . The suburb was formerly a part of Merriwa until 1998, when Merriwa was split in two along Connolly Drive. The eastern half of Merriwa was gazzetted as Ridgewood. At the time, only south Ridgewood was populated, containing the "Carnegie Private Estate" that was built in the mid-1990s. The estate had a small population of 968. There were campaigns for Ridgewood's separation from Merriwa as far back as 1994, not long after the Carnegie Estate had been built by developers Town and Country Holdings. The developers lodged a request with the City of Wanneroo to bifurcate the area from Merriwa and rename the new locality "Carnegie", after the estate, which in turn was named in honour of David Carnegie, one of the earliest explorers of Western Australia. Although the request was rejected, the City supported the excision of the estate from Merriwa, leading to the creation of Ridgewood four years later. The northern half of Ridgewood, "The Vistas", is a new development by Satterley , marketed as a part of the "Brighton Estate" that covers the adjoining suburbs of Butler and Jindalee.