||Utah has evolved from an isolated rural state of fewer than 300,000 in 1900 to a mostly urban state of 2.5 million today. This paper is an attempt to place this population growth within the context of the broadest outlines of national population dynamics over the past century. The growth and regional redistribution of the population are examined first, emphasizing the steady westward and, since the 1970s, southern movements, as well the emergence of the Intermountain region as the most recent engine of western growth. Next, the sources of population growth and redistribution over the 20th century are reviewed, identifying and contextualizing the most fundamental demographic determinants - natural increase and migration. The heart of the paper, laid out in four sections, is a detailed examination of interstate and international migration patterns among states since 1990, including special consideration of the contribution of Hispanics. One final section returns the focus to Utah, situating its demographic past within the national framework that has been explored in this paper, and drawing implications for the future of the state.