Brunswick Valley Heritage Park, Botanical garden and park in Byron Shire, Australia.

Brunswick Valley Heritage Park is a 4-hectare riverside arboretum on the Brunswick River in Mullumbimby, holding 300 species of local rainforest trees grown from seeds and cuttings collected in the surrounding forests. A timber entrance gateway on four dark brown posts, with a green corrugated metal roof and signs for the park and Maslen Arboretum, stands over a concrete path. The grounds also contain a children's playground reached via Mill Street.

In 1980 the Byron Flora and Fauna Conservation Society, led by Russ and Beryl Maslen, took charge of a weedy horse paddock that had been earmarked for a caravan park. On 7 June 1980 Mayor Stan Robinson planted the first tree, a red cedar, launching the arboretum. Volunteers have since propagated and planted local rainforest species, and Brunswick Valley Landcare now oversees the park.

The park's name honours Russ and Beryl Maslen, the local residents who led the Byron Flora and Fauna Conservation Society in establishing the arboretum; the entrance sign reads "MASLEN ARBORETUM". The site lies in the Bundjalung nation's country, and the plants collected here represent the rainforest that once covered the Big Scrub.

The park is accessible from Brunswick Terrace and Tyagarah Street, making orientation easy for first-time visitors. The walking paths are straightforward to follow, and the boat ramp and playground areas are well signposted.

The first tree planted here, on 7 June 1980, was a red cedar set in the ground by Mullumbimby's mayor Stan Robinson. The site had been a weedy horse paddock marked for a caravan park. Volunteers led by Russ and Beryl Maslen then grew the collection from seed and cuttings taken in nearby forest remnants.