A distinguishing landmark feature of Capel Sound is the Tootgarook Swamp, the largest example left of a shallow freshwater marsh in the Port Phillip bay region. The swamp is also described by Melbourne water as a ground water dependent ecosystem. The 381 hectare swamp is found on the lower section of the Mornington Peninsula, called the Nepean Peninsula in Victoria, Australia. A large portion of the Tootgarook Swamp is zoned as residential and industrial, with roughly half of the actual swamp inside the green wedge and half within the urban growth boundary.
Rosebud West Post Office opened on 12 January 1938 and closed around 1996.
On 15 September 2016 Mornington Peninsula Shire Council officially changed the name from Rosebud West to Capel Sound.