This chapter aims to contribute to the knowledge about Norwegian regional productivity in three ways. First, existing regional GDP estimates from 1965 onwards are collected and harmonized. Second, historical income data are used to extend the estimates back to 1900. Third, a preliminary analysis of the data is conducted. The collection of data on Norway has a long and extensive history. The most accurate data on Norwegian incomes come from the tax statistics. To construct a data series for gross regional product in Norway, the natural starting point is the regional GDP indices produced by Statistics Norway. For historical GDP values, estimates are based on income data. The population data are obtained from the Norwegian decennial census, which was conducted every 10 years from 1900 onwards, with the exception of 1940 and 2000–2010. N. Crafts uses income data to allocate regional GDP for Great Britain in the same period as F. Geary and T. Stark.