This dissertation examines the economic, demographic, and social dynamics of income inequality in the United States. Income inequality is high, and rising, in the United States. Given that income inequality is associated with adverse societal outcomes, it is important to understand the causes and consequences of income inequality. The first chapter examines the effects of manufacturing employment on inequality in U.S. counties, and builds on prior research by disaggregating this sector into the durable and non-durable subsectors. I find that the effects of each subsector vary over time (1990 to 2016) and by county rural-urban status. The protective effects of both durable and nondurable manufacturing have weakened over time in both rural and urban counties, but disproportionately so in urban counties. By the end of the study period, the protective effect of both subsectors was only detected in rural counties. The second chapter examines the effects of population aging on income inequality in U.S. commuting zones and examines whether these effects vary between the mechanisms of aging: aging-in-place and retirement migration. Income inequality is measured as change in the overall level of income inequality and as the shifting shape of the income distribution from 2000 to 2010. I find evidence that population aging's effect on income inequality varies by the aging mechanism. Population aging in the context of aging-in-place decreases income shares in the middle of the distribution. Population aging in the context of retirement migration increases the overall level of income inequality, decreases income shares at the bottom of the distribution, and increases income shares at the top of the distribution. The third chapter examines whether and how people living and working in a high-inequality context perceive the economic and social dynamics of income inequality. Using a case study approach, this chapter uses interview data from 12 study participants to understand the perceptions, causes, and consequences of income inequality in Hancock County, Maine. The findings indicate that participants accurately perceive that income inequality is high, and increasing, in Hancock County. Participants discussed the community's status as a New England summer colony and major tourist destination, which concentrates employment growth in the lower-wage and seasonal service industry. Participants also expressed concern that the housing affordability crisis and the AirBnB economy have hollowed out the sense of community among working- and family-aged residents with lower to moderate incomes. These three papers provide unique insight into the economic, demographic, and social dynamics of income inequality. Their distinctive contributions include analysis of the underlying components of two major economic and demographic processes in the United States (deindustrialization and population aging), as well as qualitative insight into the social dynamics of income inequality in a high-inequality context.