New Zealand Archaeological Association Site Record Number Y17/5 is a pit site that forms part of the dense archaeological landscape of the Tolaga Bay (Uawa) area. It is located on Iwinui Station, to the west of the Tolaga Bay township.

Pit sites and the many other recorded archaeological sites including pa, midden, gardens and urupa reflect the intensive Maori occupation of the Tolaga Bay from the time of initial Polynesian settlement approximately 700 years ago. Access to abundant food resources from the sea, rivers, inland forests and horticultural production (kumara) meant that a large population could be sustained. It has been estimated that the early Maori population of Tolaga Bay totalled approximately 1200; and the main iwi was Te Aitanga a Hauiti.

Pit and pit/ terrace sites are very common in Tolaga Bay, and demonstrate the importance of horticulture to Tolaga Bay's earliest inhabitants. The Bay's fertile soils and temperate climate were well suited to kumara gardening, and the pits were used for storing harvested kumara over the winter months. Rectangular storage pits (which were once roofed with a layer of earth), are more prevalent than the underground storage pits found elsewhere in New Zealand, a pattern attributed to the harder substrate of the soil in this area. They are in fact the most common archaeological site type in Tolaga Bay, and are found along the river banks and on the rolling hills to the south of the Bay. They are generally located in clusters on knolls or terraces, or on ridge crests, in lines from end to end, as found with this site -Y17/5.

Pit site Y17/5 is located on the steep east-west running ridgeline where Pukeatua trig is located, approximately 700-800 metres east of Mangaheia Road. The main part of the site extends for approximately 135.5 metres along the ridge top, which is bisected by a fence line. There are a number of other recorded archaeological sites (mostly pits and pits/ terraces) in the vicinity, such as pit site Y17/127, approximately 270 metres north along the ridgeline.

This site was first recorded by field workers from the Gisborne Museum in 1971. It was described as a 'ridge site with pits but no defensive earthworks'. The main part of the site extended along the ridgeline, both to the east and west of the Pukeatua Trig. Pits were also noted in two places on the lower approaching ridges to the west. A sketch plan of the site shows a total of six pits; three are located in a row at the western end of the site, and a further three are located at the eastern end, two of which are positioned side by side. A terrace (0.3 metres deep) is also illustrated at the eastern end of the site.

Pit site Y17/5 was revisited by the New Zealand Historic Places Trust in November 2007 and was found to be as originally recorded. However, the pits on the southern side of the fence line were in long pasture and in better condition than those on the northern side though, which had been damaged by stock tracking. A large slip was also noted on the northern side of the fence line. The easternmost pit (which lies to the north of the fence line) was still clearly visible however. A subsequent inspection of a 2008 Google Earth aerial photograph has revealed a possible defensive earthwork feature at the western end of the site (on the southern side of the fence), and some possible pits/ terraces to the south of the eastern end of the site. These features will need to be field checked on the ground at a future date.

Y17/5 is one of numerous pit and pit/terrace sites recorded in the Tolaga Bay area. It is part of a dense archaeological and cultural landscape that is of considerable significance to Te Aitanga a Hauiti, reflecting the intensive Maori occupation and settlement of the Tolaga Bay area since the 14th - 15th centuries AD, and the important role that horticulture played in this.