In this thesis, I study the impact of minimum wage policy and city agglomeration on wages and employment in local labour markets. This is an important topic because having a better understanding of the determinants of regional wage differentials and employment offers insights into: the roles played by local production, consumption and city structures; the standard of living enjoyed by workers with different human capitals; and policy recommendations for the future minimum wage law and city planning regulations. I use local occupation and geographic information to assess how highly productive occupations and local consumption amenities sort workers and generate local wage differentials. I also use this information to construct instruments that enable the accurate estimation of the effects of policy interventions. After an introduction in chapter 1, chapter 2, The Impact of the Minimum Wage on the Wage Distribution: Evidence from China, provides an empirical estimation of the effects of minimum wages using a Chinese household survey. I introduce new instrumental variables, relating to transport costs and local productivity, to control for the potential median wage endogeneity. The instrument variable regressions indicate that the effective minimum wage, defined as the ratio between the minimum wage and the median wage, significantly reduces the lower tail wage inequality — measured by the wage differential between the 50th and the 10th percentiles— by up to 0.3 per cent. In chapter 3, The MinimumWage and Its Impact onWage and Employment, joint work with Coen Teulings, we propose a novel framework for estimating the effects of minimum wages by considering the neoclassical wage and labour participation equations at the same time. To estimate the non-linear censored model with correlated error terms, we provide a five-step procedure and use maximum likelihood estimation. After correcting the bias using occupation information and city size, we find that effective minimum wage correlate significantly with the proportion of workers earning below minimum wage. I study the structure of city and commuting in chapter 4, Consumer City and the Sharing Economy. Based on the international trade literature, I develop a theoretical model with multiple cities, which have different amenities and productivities. In equilibrium, the unobservable parameters are estimated using local employment, wage, and commuting information. Cities show strong agglomeration effects in both productivity and consumption amenities. A counterfactual technological improvement, providing a cheaper transportation for workers and consumers, leads to a more concentrated employment distribution, commuting pattern and higher utility. In the final chapter, Agglomeration and Sorting, joint work with Coen Teulings, we show that agglomeration externalities are strongly related to the occupational structure. At the same time, regional differences in house prices offset these externalities. We develop a multi-region model with regional heterogeneity in workers and jobs, tradable versus non-tradable commodities, consumption amenities, regional house prices, non-homothetic utility, and interregional labour mobility. The model fits the regional data on the fixed wage effects, the return and mean level of human capital, land prices, and the city-rural area distinction well. We use land values to calculate the value of agglomeration.