A steam-powered flour mill opened in 1857. After a competing mill in nearby Drysdale was destroyed by fire in 1861, Portarlington began to develop more rapidly. At that time, the Bellarine Peninsula was regarded as the granary of the Victorian colony. The mill owners built a private jetty, and began receiving grain shipments from Geelong and shipping out the flour and bran produced. A post office opened on 1 March 1863 (known as Port Arlington until about 1866, although that may have been in error).