New findings reveal how postal infrastructure significantly boosted economic outcomes in both short-term and long-run analyses.

Original Data & Methods: We merged cross-national data from 1875-2007 with U.S. county-level records spanning 1850-2000 to track the spread of postal systems across countries.

Key Findings: Postal establishment consistently improved local economic performance regardless of dependent variables or model specs, showing robust effects across different measures and time frames.

Causal Mechanisms: The evidence points strongly to two core benefits: reduced transaction costs for businesses and strengthened social capital in communities through reliable mail services.

This research highlights how statebuilding via public infrastructure like postal systems can produce enduring economic development outcomes, providing a tangible pathway from institutional investment to prosperity.