Seton Nossiter Park is a 30ha protected natural reserve nestled in the steep gullies between the surrounding suburbs of Grenada Village and Horokiwi to the north, Woodridge to the east and Newlands and Paparangi to the south. The embankment of the Northern motorway forms the western boundary. The park is 1.6 kms long.

The Belmont Stream flows through the park and is a prominent and attractive feature. It is a major tributary of the Porirua Stream that flows from Glenside through Tawa to the Porirua harbour.

The main entrance to the park is from Mark Avenue, Grenada Village, where there is a parking area and a service road down into the main valley floor.

Seton Nossiter Park provides several walking tracks through native bush. There are open space areas, streams, and several picnic spots. It is very sheltered and has its own micro-climate due to its low lying nature to the surrounding hillsides. It provides a natural environment for recreational use and enjoyment. The park is used for a variety of activities including use by the three neighbouring schools for nature study, bush-craft, local history studies, and cross-country runs. It is a haven for informal recreation and natural atmosphere.

The park not only provides an important vegetation link between the adjoining suburbs, but also presents a bird and wildlife corridor between the eastern harbour escarpment, the Belmont Gully and ultimately the Belmont Regional Park. Some of the birds sighted in the park are the native pigeon, tui, fantail, waxeye, morepork, grey warbler, long-tailed and shining cuckoo, grey duck and kingfisher. Bell-birds have been heard. This is in addition to the regular quail, magpie, sparrow, starling, blackbird and skylark. A remnant titoki-tawa forest is located on the valley floor near the traditional picnic site and extends up the slopes on both sides of the valley.

The park is part of the Wellington Outer Town Belt that runs in continuous sections in a northerly direction from the southern coast, through Karori to Otari to Mt Kau Kau and on to Porirua (west of the motorway) while branching to the east at Glenside through Seton Nossiter Park to Belmont.

There is an information panel erected at the entrance from Mark Avenue depicting the history of the Belmont Viaduct that was constructed in 1885 and traversed the gully as part of the Wellington & Manawatu Railway Company. The viaduct was one of the great engineering achievements of 19th century New Zealand and is a distinctive and memorable part of this country's early transport system. The original gigantic wooden trestle span not only played a significant role in developing early Wellington, but also eventually became part of the North Island main truck line. It was the largest wooden structure of its kind in New Zealand. The viaducts original foundation abutments are not far from the main entrance and remain clearly visible.

The park has featured in the Wellington City Council's booklet 'Branching Out' and was described as "one of Wellington's best kept secrets and one of the most historical places around".

Under the Reserves Act 1977, the park is a recreational reserve that gives priority to outdoor recreational activities, walking tracks, open spaces and protection of the natural environment. Under the provisions of the Act, the Wellington City Council were required to prepare a Management Plan for the park to guide its management and development for the next ten years. The Plans purpose and role is to: "provide for and ensure the use, enjoyment, maintenance, protection, preservation and development of the reserve for the purpose for which it is classified". It ensures that the natural character of the Park will be retained and enhanced where possible. The plan became operational in August 1996.

To ensure that there was direct local input and community representation in the preparation and development of the plan, the Seton Nossiter Park Working Group was established. This working group represented a large number of local community groups, park users and other local people. It was also formed to ensure that the communities and other park users interests were identified and recognised.

How did Seton Nossiter Park get its name? The land was purchased by the City Council in 1979 from Ray Turkington. The Council's Reserve Committee decided to name if after Seton Nossiter of Ohariu Valley, as recognition for his contribution to various local body activities in the area. Mr. Nossiter was a member of the Hutt County for the Makara Ward from 1966 until the area became part of Wellington City. He was then a City Councillor until 1977. At the time, two other names were put forward for consideration. One was 'Viaduct Park" because of the park's historical association with the Wellington & Manawatu Railway Company and another was Grenada Park after the development and obvious close affiliation with Grenada Village