Ōizumi is a town located in Gunma Prefecture, Japan. As of 31 August 2020, the town had an estimated population of 41,918 in 19,773 households, and a population density of 2300 persons per km2. The total area of the town is 18.03 km2 (6.96 sq mi). Approximately 20 percent of the total population are foreign citizens, mostly Japanese Brazilians, who work at many factories in the town. Since 1990, Japanese descendants from foreign countries have been permitted to stay in Japan freely. It is estimated that 15 percent of the population speak Portuguese as their native language, and as of 2007, Ōizumi has the highest concentration of Brazilians of any city in Japan. More recently, Nepalese and other Asians have begun settling in the town.