The economic base of North Dakota and its eight substate regions has changed over the past couple of decades. This report takes an in-depth look at the economic base for each of these areas over the 1958-1984 period. Each of the regions has a unique composition of basic activities that have been responsible for its growth. Natural resource related activities, either in the form of agricultural or energy production, have been the largest source of real economic growth within the state. The purpose of this report is to identify the components of the economic base at substate levels and to show the changes in relative composition for these activities. Price and production data are presented to support and explain the changes that have occurred.