Asignificant portion of a popular Millicent park is set to pass out of public ownership for the first time in 150 years.

Apex Park near the George Street roundabout was created in the 1960s by members of the now-defunct Millicent Apex Club on parklands and a railway reserve.

A Millicent real estate company has announced the sale of the railway reserve which has grassed areas, around a dozen mature pine and poplar trees and a 50-metre portion of broad-gauge rail line.

Almost a year ago, a Mount Gambier fuel company announced plans to build an unmanned retail outlet on the site which fronts National Highway One.

According to the documents lodged with Plan SA, the trees will be felled, grassed areas paved and the rail tracks and rubble base removed.

The petrol station will have the usual pumps, signage, lanes etc.

The railway reserve land in various parcels was put on the open market in early-2019 after being in the ownership of the State and colonial governments since the 1870s.

One parcel was purchased by Millicent Farm Supplies and is now its storage yard.