A methodology for estimating a state's gross state product (GSP) from primary data sources is presented and applied to Ohio. The social accounts for estimatingGSPare used as a skeletal framework orf building a 27 equation econometric model of Ohio. The model is essentially an interdependent system consisting of behavioral equations in the following sectors: consumer, investment, state fiscal, output and personal income, and federal income tax. The sample period for most of the equations is 1949–1963.