College enrollment, the process in which families make investments for the future, individuals receive higher education and seek self-improvement, and an aspect closely related to the lives of everyone in a modern society. The trends of college enrollment have been fluctuating due to various factors throughout history, mostly due to socioeconomic factors. In this article, multiple linear regression models are constructed to analyze and evaluate how some possible factors are correlated with the fluctuations of college enrollment in the United States each year from 1973 to 2022. Data for dependent and independent variables were gathered from government and non-profit organization websites such as the Federal Reserve Bank of St. Louis, the United States Census Bureau, and the Educational Data Initiative. The results have shown that many factors are influencing the fluctuations, with GDP and income being the main factors; this article provides a supporting role in making admission policies and country developments.