|⁃ location||Goonac siding|
|⁃ elevation||219 metres (719 ft)|
|Length||84 kilometres (52 mi)|
|Basin size||113,957 hectares (281,594 acres)|
|⁃ average||1,098 ML/a (0.0348 m3/s; 1.229 cu ft/s)|
The river has a total length of 84 kilometres (52 mi) and rises near Goonac siding then flows in a north-westerly direction until discharging into the Leschenault Estuary. The headwaters are 80 kilometres (50 mi) inland within the Darling Range and run across the Blackwood Plateau and the Swan Coastal Plain.
The majority of the river catchment has been cleared for agriculture although some remnant forest vegetation exists at the headwaters.
The major tributaries of the river include the Ferguson River and Joshua Creek. Minor tributaries include Thomson Brook, Crooked Brook, Charley Creek, Waterfall Gully, Mininup Brook, Millbrook and Gavin Guly. The Glen Mervyn Dam is along the Preston River.
The river basin is monitored routinely as a result of eutrophication problems within the Leschenault Inlet. The water quality is fresh in many places and generally low in nutrients although some areas are slightly enriched with nitrogen.
- "Bonzle Digital Atlas - Map of Preston River, WA". 2008. Retrieved 23 November 2008.
- "Australian Government - Bureau of Rural Sciences - Preston River" (PDF). 2008. Retrieved 23 November 2008.
- "Australian Natural Resources Atlas - Economics - Preston River". 2007. Retrieved 23 November 2008.
- "The Leschenault Estuary - A changing environment". 2007. Archived from the original on 20 July 2011. Retrieved 23 November 2008.
- "Australian Natural Resources Atlas - Preston River Basin". 2007. Retrieved 23 November 2008.