The impact of the foreign population on Japan is increasing every year, and it has become essential to analyze the regional trends of the foreign population for future population projections by region, which are conducted by the National Institute of Population and Social Security Research. This chapter aims to organize basic information for this purpose and examines the characteristics of the regional distribution of the foreign population in recent years, primarily from the reference table of the 2020 “Population Census.” Compared with the Japanese population, the foreign population tends to be concentrated in metropolitan areas, primarily in the Tokyo metropolitan area, a trend that has increased during 2015 → 2020. The concentration of population in the Tokyo metropolitan area is often considered in the context of internal migration, but the distribution of foreigners primarily owing to international migration also contributes to it.