Auckland was the largest of the original six provinces of New Zealand both in population and in area. Despite separation movements in the outlying districts of Poverty Bay and Northland, Auckland maintained its unity until the abolition of the provinces in 1876. When the provincial boundaries were defined in 1853 the North Island interior was little known to the white man and the southern boundary of Auckland was drawn simply as the thirty-ninth parallel of latitude between Mahia Peninsula, on the east coast, and the Wanganui River. After 1876 the provincial district continued to be an administrative division for the Department of Lands and Survey, but with the expansion of settlement it proved too large a unit and was eventually divided into three land districts: North Auckland, South Auckland, and Gisborne. The arbitrary line of the thirty-ninth parallel was replaced by boundaries conforming more realistically to the surface configuration. Thus small areas of the Wellington and Hawke's Bay Land Districts extend into the former Auckland Province and a small area of the South Auckland Land District is in the former Wellington Province. The ties of community of interest between the Gisborne–East Cape district and the rest of the province have never been strong, and trade and communications have been with the southern North Island rather than with Auckland.

At the time of its establishment in 1853, the Auckland Province contained about one-third of the 30,000 European settlers in New Zealand and an estimated 70 per cent of the Maoris. By 1861 Auckland's European population was surpassed by that of Otago and, briefly, between 1878 and 1886, Auckland fell to third place after Otago and Canterbury. By 1901 the Auckland Provincial District once more regained first place and, thereafter, the gap between it and all other districts steadily widened. If the Maori population is included in provincial totals (the Maori numbers in the nineteenth century are not known with certainty) it is probable that Auckland has always been the most populous province.

Auckland has a longer history of continuous European enterprise than any other province, but unlike the other five original provinces its settlement did not originate in planned colonisation by a relatively homogeneous group. The population has always been more varied in race and origin than that of the other New Zealand provinces. Not only has Auckland always contained the greater part of the Maori population, but it has also been a focus for continuing migration from overseas. In 1956 the provincial district accounted for 40 per cent of the total New Zealand population, but it had the majority of the country's Pacific Island immigrants, 80 per cent of those born in Yugoslavia, 59 per cent of the Canadian born, 56 per cent of those of United States birth, 46 per cent of the Australian born, and 55 per cent of the Indian born.