The historical evolution of the geographic distribution of economic activity across Pennsylvania is examined. As the state developed, it first experienced increasing population and manufacturing spatial inequality with manufacturing concentrated in Philadelphia and, eventually, Pittsburgh. Inequality reached a peak in the 1930.s. Since then, population and manufacturing have become more dispersed across the state, with the counties in the southeastern portion of the state accounting for an increasing proportion of all economic activity in Pennsylvania. Agriculture has shown the opposite pattern: initial dispersion followed by increasing concentration, again in the southeastern part of the state.