Why has Melbourne expanded more toward the east than toward the west?

The expansion of Melbourne has been primarily eastward due to significant geological and environmental differences between the city's eastern and western regions.1

To the west of the original city site, the landscape is characterized by flat, uniform plains formed by basalt flows during the Cenozoic Era. In contrast, the eastern region consists of undulating terrain composed of sandstones, shales, and conglomerates. Historically, the eastern region featured thicker soils and higher annual rainfall, which supported a much denser cover of trees compared to the basalt plains of the west.1

These environmental factors influenced the city's development, leading to a strikingly asymmetrical urban footprint. While Melbourne’s development lines the entire eastern shore of Port Phillip Bay for 60 miles (97 km), corresponding development on the western side of the bay extends for only 10 miles (16 km). Over time, the eastern suburbs became a preferred area for growth, supported by the availability of large, inexpensive land and an increasing population following World War II.12