The Västra Mölndalsån FVOF covers the Mölndalsån from the old parish border between Landvetter and Härryda, which runs approximately at Kroksjövägen in Snåkered to the inlet of Rådasjön, including the lakes that drain into Mölndalsån (with a few exceptions). Lakes included are Dammtjärn, Agntjärn, Landvettersjön (Gröen), Stora and Lilla Hålsjön on the border between Partille and Härryda municipalities, Stora and Lilla Brastjärn (Tutjärn) in Partille.

The area within the fenced area of the Mölnlycke factories is not included in the fisheries conservation area.