West Toodyay (previously known as Toodyay, Old Toodyay) was the original location of the town of Toodyay, Western Australia. The site was first identified in 1831 by Robert Dale, and the area was surveyed in 1833 with a town established in 1836. In the 1850s it had been affected by flooding, causing the residents to move; in 1860 the new town of Newcastle was established 3 miles (4.8 km) to the east. Newcastle was renamed in 1910 to Toodyay, and the original site became known as West Toodyay.
The town of Toodyay was established on the bank of the Avon River where the valley gave way to gentle slopes of fertile soils with hills on all sides. The main street was South Terrace, which was aligned to the river's course and was crossed by six streets. A second road paralleled South Terrace rising on to the ridge behind the town. The town had a number of home, stores, a school, a hall and two churches. The town also had three inns: The Queen's Head, The Royal Oak and The Highland Laddie. Flooding in 1862 washed away all trace of The Highland Laddie.
The Royal Oak was one of three inns in the town of Toodyay; it was the centre of social activity for the town. The Northam, Toodyay, and Victoria Plains Agricultural Society, later to be known as the Toodyay Agricultural Society, held it first meetings at The Royal Oak. During October the Society held its annual dinner, which was attended by the Governor of Western Australia, who would also attend the Toodyay Agricultural Show and tour the region.
In 1851 a convict establishment was set up to the east of the town. Following severe flooding in 1857 and 1859, a new town was established in 1860 near the convict settlement; it was named Newcastle, after the Duke of Newcastle.
On 6 May 1910, it was declared that the town of Newcastle would henceforth be known as Toodyay, and the old town of Toodyay would henceforth be known as West Toodyay.
In 1920 the West Toodyay school was closed and its 24 students were transferred to the Toodyay school as part of the "consolidated schools" plan, an experiment based on practices in the US and Canada where larger schools were considered more advantageous to children's education. In 1928 the West Toodyay school building was sold by tender and removed.
The location "West Toodyay" on the Western Australian Government Railways narrow gauge railway system was the point where the Clackline-Miling railway headed north, and crossed the Avon River.
With the development of the standard gauge railway line through the Avon Valley in 1966, West Toodyay was a junction where the narrow gauge Miling railway connected with the newer standard gauge system, and a marshalling yard existed.
In the de-regulated railway system, West Toodyay yard is now a shire depot, a crossing loop location, and a junction where the Miling railway proceeds north over the Avon River.
During the era of the Spirit of the West railway service, the location was also known as the Avon Siding, due to the lack of any crossing or shunting facility at the Toodyay railway station site.