In 1825, John Phillips Webber established his Penshurt estate in present-day Mount Rivers.[2][3] The estate was sold in 1834 to George Townsend for a thousand pounds. The land was subdivided into 6 lots in 1855 and then further subdivided into 10 lots in 1914. A post office was opened in 1861, and a telephone exchange opened at the office in 1917. The post office was moved to a new site in 1927 after the land was sold, and moved again in 1931. After the resignation of the postmistress in 1966, the post office was permanently closed in 1967.[4]
Mount Rivers was well known for its cheese circa 1900. A cheese factory was established by Alfred Holden, procuring a considerable reputation, with its produce being sold as "Penshurst" cheese in Maitland[5]
Initially, Mount Rivers had a private school. It was converted to a public school in 1875. A decline in enrolments forced it to cease as a public school in 1924.[4] However, through subsidisation, it continued to exist, and in 1939 it reopened as an official public school. Eventually, the school was closed in 1981.[6]