This paper estimates the impact of the US-Mexico border fence on US-Mexico migration by exploiting variation in the timing and location of US government investment in fence construction. Using Mexican survey data and data I collected on fence construction, I find that construction in a municipality reduces migration by 27 percent for municipality residents and 15 percent for residents of adjacent municipalities. In addition, construction reduces migration by up to 35 percent from non-border municipalities. I also find that construction induces migrants to substitute toward alternative crossing locations, disproportionately deters low-skilled migrants, and reduces the number of undocumented Mexicans in the United States.

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隔离：边境建设对美墨移民的影响

本文通过利用美国政府投资围栏建设的时间和地点的变化来估计美墨边境围栏对美墨移民的影响。使用墨西哥的调查数据和我收集的围栏建设数据，我发现在一个自治市的建设减少了 27% 的自治市居民和 15% 的邻近城市居民的迁移。此外，建设可将来自非边境城市的移民减少多达 35%。我还发现，建设促使移民替代其他过境地点，不成比例地阻止了低技能移民，并减少了美国无证墨西哥人的数量。