The size of Deans Marsh is approximately 57.1 square kilometres for ABS data collection purposes.
The population of Deans Marsh in 2011 was 372 people and by the 2016 Census the population was 256 showing a population decline of 31.2 per cent in the area during that time.
Deans Marsh is a picturesque rural village just north of the Otway State Forest and 27 km east of Colac.
Deans Marsh was thought to be named after Charles Dean, who held a grazing licence in the area from about 1846. Surveyed farms were taken up during the early 1860s, and a school was opened in 1865 with a store being built in 1868.
In the late 1870s Lorne became a popular resort, Erskine House and Lorne Hotel were opened in 1878 and the Deans Marsh hotel was a coach stop on the journey.
Within the next 10 years Deans Marsh gained an Anglican church (1884), a public hall and the extension of the railway line from Birregurra (1889).
Deans Marsh has a popular general store and café.
There is a commemorative plaque at the cottage where the operatic singer Marjorie Lawrence (1907-79) was born.
CoreLogic data indicates that the predominant age group in Deans Marsh is 40-49 years with households in Deans
Marsh being primarily childless couples and are likely to be repaying $1,800 – $2,399 per month on mortgage repayments, and in general, people in Deans Marsh work in a managers occupation.
In 2011, 82.3 per cent of the homes in Deans Marsh were owner-occupied compared with 76.3 per cent in 2016.