The 'Last Spike' Memorial commemorates the completion of the North Island Main Trunk Line (NIMT).

The concept of a railway line joining New Zealand's two main North Island cities was first put forward by the then Colonial Treasurer Julius Vogel (1835-1899) in 1870. To achieve Vogel's vision, approximately 200 miles (322 kilometres) of rail would have to be constructed between Marton and Te Awamutu, to connect the lines that were already in operation. An Act enabling finance for the scheme to be raised was passed in 1882, and the following year government surveyors received permission to map a route through the King Country in the Central Plateau. Work on the line began in 1885 and, having overcome the significant engineering challenges presented by the mountainous Ruapehu region, was completed 23 years later in 1908.

To mark the occasion, the then Prime Minister Sir Joseph Ward officiated at a ceremony during which he drove the official last spike of the NIMT, apparently joining the two railheads and the cities of Auckland and Wellington thereby. In fact, work was still being undertaken on the line, and the actual last spike was driven at the Manganui-o-te-ao Viaduct approximately 300 metres away. Regardless, the crowds flocked to mark the occasion which was considered, in itself, to be worthy of recognition by the erection of a monument some time later.

This monument, the 'Last Spike' Memorial, is a plain concrete obelisk on a concrete base. It is significant for its commemorative value of both the completion of the NIMT, and of the NIMT itself, which both revolutionised travel and had ramifications for race relations, politics, land settlement, and trade. An integral part of the wider historical and physical landscape of the railway line, the memorial stands as a reminder to the public of the impact of the NIMT on New Zealand's history.