Cullen Reserve consists of 29 hectares of native bushland between Lake Fellmongery and Beacon Hill in Robe, SA. It is a listed Heritage Vegetation property and provides valuable habitat for several threatened species including the common wombat and Little Dip Spider Orchid.

In 1968, Robe residents Dick and Ida Cullen were encouraged by local real estate agent Rick Cawthorne to donate the reserve to the Natural History Society of South Australia Inc. for dedication as a wildlife reserve in perpetuity. Members of the Society have re-vegetated sections of the reserve which was once used as a trap shooting range, a sand quarry and as a dump. Some of this revegetation had to be protected from rabbits with a wire mesh fence. Today there is an extensive ground covering of muntries, and many other local plant species and rabbits are rarely seen.

The reserve protects remnant vegetation with stands of dry land tea tree (Melaleuca lanceolata) and coastal mallee (Eucalyptus diversioflia), a large area of the traditional bush tucker muntries (Kunzea pomifera) and protects a population of the threatened Little Dip Spider Orchid (Caladenia richardsiorum).

Re-establishment of native flora has brought back some of the original inhabitants such as the common wombat which had not been observed in the reserve until they returned in 2004. The reserve also provides habitat for many bird species including red capped robins, superb blue fairywrens, beautiful firetails, rufous bristlebirds and yellow robins.