The line runs between Motoyawata in Ichikawa, Chiba in the east and Shinjuku in the west.

On maps and signboards, the line is shown in the color leaf green.

Stations carry the letter "S" followed by a two-digit number inside a yellow-green chartreuse circle.

[2] According to the Tokyo Metropolitan Bureau of Transportation, as of June 2009 the Shinjuku Line was the third most crowded subway line in Tokyo, at its peak running at 181%[a] capacity between Nishi-ōjima and Sumiyoshi stations.

^ Crowding levels defined by the Ministry of Land, Infrastructure, Transport and Tourism:[6][7]