Mount Napier is an inactive volcano, created through the build up of lava flows and scoria, with the last eruption being estimated at 32,000 years ago. The volcano is a relatively new volcano in the Victorian region.
The mount rises to 440 metres above the surrounding plains and is the highest point in the western district of Victoria.
The flow from the Mount Napier eruption travelled west and then south and lava caves and volcanic blisters can be seen along the route.
The Byaduk Caves, formed by this lava flow, are a part of the park.
Access to the volcano is possibly from the park and one can climb to the very top. The park also includes manna gum and blackwood forests.