Small Island of Salt Marsh accessible only by boat.

A relatively uniform deciduous swamp occurs throughout the property except the northwest corner, which lies slightly upland.

The Spring Brook runs south west through the reserve and meets up with the Shingle Island River, which forms the southern boundary of the property.

The under growth of Ashton Reserve is primarily cinnamon fern, sweet pepperbrush, and bull brier. The property also contains two brooks.