North Dakota’s economic base is comprised of those activities producing a product paid for by nonresidents, or products exported from the state. North Dakota’s economic base activities include agriculture, mining, manufacturing, tourism, and federal government payments for construction and to individuals. Development of the North Dakota economic base data is important because it provides the information to quantify the state’s economic growth, and it creates the final demand sectors for the North Dakota Input-Output Model. This report provides a brief description of the methodology used to estimate each individual sector and the associated data sources. Sales for final demand have been estimated for the 1958-2007 period. Personal income generated by the North Dakota Input-Output Model can be compared to Bureau of Economic Analysis values to validate the model. For the 50-year period the state’s economic base has been estimated, the absolute average difference from Bureau of Economic Analysis personal income was 7.19 percent.