The river valley is the centre of the catchment of the Helena River and extends from the edge of the Darling Scarp where Boya, Gooseberry Hill and Helena Valley define the "mouth" of the valley that opens to the Swan Coastal Plain, east and south east past Mundaring Weir and Lake C.Y.

O'Connor to its origins in the region of Mount Dale.

The soils of Helena Valley are characteristic of the eastern Swan Coastal Plain, ranging from sand to loam and clay, with a neutral pH tending towards moderately acid.

[2] The locality is within the Shire of Mundaring, situated just south west of Boya and Greenmount Hill, 5 kilometres from Midland.

Helena Valley Primary School is located at the base of Greenmount Hill.