This house is significant as the home of Dame Ngaio Marsh (1895-1982), the world-renowned crime writer, from 1907 until her death in 1982. One summer, when Ngaio was a child, her parents, Rose and Henry, were lent a cottage in the Cashmere Hills. This experience persuaded them to purchase land in Cashmere and build a house there. Samuel Hurst Seager, the noted Christchurch architect and a relative of the Marshs, was asked to design the house.

Whilst the exterior of the house has been altered over the years, the interior remains intact, including the timber panelling and built-in bookcases characteristic of Seager's domestic work. Dame Ngaio described the house when newly built in her autobiography Black Beech and Honeydew: 'The new house smelt of the linseed oil with which the panelled walls had been treated and of the timber itself. It was a four-roomed bungalow with a large semi-circular verandah. The living room was biggish. There were recesses in its bronze wooden walls and there was a pleasant balance between them and the windows.'

Dame Ngaio studied at the Canterbury School of Fine Arts. As well as painting she wrote, and toured as an actress. During the 1920s she lived on the sale of her paintings, writing articles and stories, coaching drama and directing plays. In 1928 she made her first trip to England, and in 1931 her detective novel, A Man Lay Dead, appeared; the first of over thirty novels to be published. In 1932 she returned to New Zealand as her mother was ill. For the next thirty years Dame Ngaio wrote detective novels, articles, and stories, produced Shakespearean plays and often travelled to London. She was made a Dame Commander of the British Empire in 1966 for her work in drama and in 1977 she received a Grand Master Award from the Mystery Writers of America.

Her house in Cashmere was extended over this thirty year period. In 1948 the architectural firm, Helmore and Cotterill, designed an extension to what had been Dame Ngaio's bedroom. Renamed the 'long room', it became Dame Ngaio's living room, and she designed the colour scheme, which still exists, of deep blue-grey walls and a white ceiling. At the same time the building at the rear of the main house, originally the washhouse, was made into a studio. Later this structure was pulled down and replaced by the current building in order to provide accommodation for a housekeeper. In 1980 a new studio was built below the front bedroom to cater for Dame Ngaio's worsening health.

Dame Ngaio died in 1982 and the house was left to a relative, who let the property for a number of years. In 1992, when the house was put up for sale, a trust was formed to purchase the property. Today it is run as a museum in memory of Dame Ngaio and contains much of her furniture and objects.

The house is significant as the home of Dame Ngaio Marsh for over seventy years. Today, as a house museum, her former residence illustrates the three major aspects of her life; her writing, her involvement with drama and her work as a painter. The house also illustrates Seager's ability with small-scale domestic architecture.