The province was equal in size to the combined areas of present-day Saitama Prefecture, the part of Tokyo east of the Sumida River (excluding Shimakyo), and the northeastern part of Kanagawa Prefecture (all of present-day Kawasaki City and the eastern and coastal parts of Yokohama City).
現在の埼玉県、東京都の隅田川より東の地域と島嶼を除く部分、および神奈川県の北東部（現在の川崎市全域と横浜市東部・沿岸部）を合わせた地域に当たる。