The construction of the Main Trunk railway provided the initial impetus to the settlement of the region. Europeans, especially missionaries, had appeared on the fringes of the region in the earliest period of settlement. The Wesleyans were established at Kawhia Harbour in 1834 and at Arapae (near Piopio) in 1843, and at this period prosperous Maori farms were established north of Otorohanga. As a result of the Maori Wars, most of this prosperity was destroyed and in 1864 the boundaries of the King Country were drawn, prohibiting white settlement south of Te Awamutu. The prohibition was lifted in 1885 and two years later Te Kuiti became the railhead. From that time until after the First World War, European settlement pushed southwards, eventually linking with pioneer farms established along the Main Trunk in the valley of the Rangitikei and towards Ohakune and with those which had been established along the Stratford-Whangamomona route.

In 1911, three years after the completion of the Main Trunk, the total population numbered only 15,043 and Te Kuiti and Taumarunui each had few more than 1,000 people. By 1936 the population had doubled, both in the rural and in urban areas, but in the following 15 years the rural population increased by only 167 persons. These general figures obscure a number of divergent trends. The population of the dairying areas, as represented by Otorohanga County, continued to increase (by 700 persons) and the more favoured ridings of Clifton County increased slightly or maintained their population. In Waitomo County the population of the Tangitu riding increased by 633, the Mahoenui riding by 190, whilst the population of the Aria and Awakino ridings decreased by 268 and 305. The total population, both of Ohura and of Whangamomona counties, fell by 273 and 500. It was in Whangamomona that the most spectacular and therefore the most memorable setbacks to pioneering ambitions occurred, as is evidenced by the case of Aotuhia.