At the core of the Western Interstate Commission for Higher Education's (WICHE's) mission to ensure access and excellence in higher education for all citizens of the West, WICHE's 10th edition of "Knocking at the College Door" provides detailed data and projections of the number of high school graduates for the nation, four geographical regions, and the states, including public high school graduates by race/ethnicity. Although these projections do not account for the impact of the COVID-19 pandemic on K-12 enrollments and graduations -- because data for the high school graduating Class of 2020 have not yet been reported by states -- they still show important trends and are an essential benchmark for monitoring and understanding the impact that the pandemic has on different groups of students. The data also provide an important measure of how the improvement in graduation rates is offsetting some -- but not all -- of the expected declines in the number of graduates due to declining birth rates. Additionally, the projections show continuing trends of diversification among public high school graduates, with students of color expected to make up an even greater share of the graduating class in the future. Six key findings emerged from this edition of "Knocking at the College Door": (1) Nationally, the number of high school graduates is expected to peak in the mid-2020s before entering a period of modest decline through the end of the projections in 2037; (2) These projections show an increase in the number of graduates of about 10 percent over the previous projections; (3) COVID-19 introduces significant uncertainty into the projections; (4) Increased diversification of the graduating classes is a projected trend; (5) Private school enrollments have been more volatile than previously projected but have shown strong growth in recent years; and (6) Significant state and regional variation are important features of these projections. [For the 9th edition of this report, see ED573115.]