Book excerpt: This dissertation explores three topics in Urban Economics and International Trade. Chapter 1 measures the effect of transit access on neighborhood incomes by exploiting a quasi-experimental setting in Dallas. I show that income in neighborhoods that received rail access increases compared to neighborhoods that were promised to receive access but did not receive it. The treatment effect is positively correlated with initial neighborhood income and highlights the role of transit as an incubator for income segregation. Chapter 2 estimates the impact of international conflict on bilateral trade relations using several incidents of politically motivated boycotts. I find large reductions in exports from the boycotted to the boycotting countries. Product-level results are in line with intuition and most effective for consumer goods while having at most a temporary effect on intermediates and capital goods. Chapter 3 explores the usage of Landsat satellite imagery for the measurement of economic outcomes at small geographies.