Internal Borders and Population Geography in the Unification of Italy

We examine the economic impact of Italian unification from a micro-geographical perspective, asking whether the abolition of internal borders caused a redistribution of economic activity towards the former border zones, which now enjoyed improved market access. We construct a new geocoded dataset of municipal (comune) populations from the pre-unification period through to 1871. Using a difference-in-differences approach and controlling for a variety of geographic correlates including elevation and distances to ports, railway lines, and large cities, we find robust evidence of a relative acceleration in population growth - our proxy for economic activity - in comuni near the former internal borders, consistent with our market access hypothesis.