According to "The Shoku Nihongi," when the Koma County was established in Musashi Province in 716, 1799 Koguryo nationals who were brought over from the 7 Provinces of Tokaido Road were transferred to the Koma County.
『続日本紀』によると、716年（霊亀2年）、武蔵国に高麗郡が設置された際、東海道七ヶ国から移された1799人の高句麗人を移したという。