Most of the regional inequality in Argentina, Chile, and Uruguay stems from differences within the countries rather than from disparities across them. Between the end of the nineteenth century and the second third of the twentieth century, Chile evinced considerable inequality and a U-shaped evolution (reduction of inequality and a slight increase in the 1960s), Uruguay a monotonically declining inequality, and Argentina a U-shaped evolution with decreasing disparities until the beginning of the twentieth century and increasing inequality thereafter. Together, the subnational units exhibited substantial inequality at the end of the nineteenth century, a low in the 1940s, and another local maximum that ended with the collapse of the Import Substitution Industrialization (isi) polices of the 1960s and 1970s. Convergence at the national level depended on periods and countries: convergence in Uruguay in all sub-periods; provincial convergence in Argentina only during the first globalization; and a general convergence in Chile that was hampered by outliers during the first globalization. Convergence at the regional level occurred during the first globalization but not during the mid-twentieth century.