Portage and Path Dependence *
研究了美国南部、中大西洋和中西部河流搬运点的历史优势如何长期影响经济活动，发现即使原始优势消失，这些地点仍持续重要，体现了路径依赖效应。
We examine portage sites in the U.S. South, Mid-Atlantic, and Midwest, including those on the <i>fall line</i>, a geomorphological feature in the southeastern U.S. marking the final rapids on rivers before the ocean. Historically, waterborne transport of goods required portage around the falls at these points, while some falls provided water power during early industrialization. These factors attracted commerce and manufacturing. Although these original advantages have long since been made obsolete, we document the continuing importance of these portage sites over time. We interpret these results as path dependence and contrast explanations based on sunk costs interacting with decreasing versus increasing returns to scale.