The Tokyo Settlement (Toukyou Sokai), is the administrative capital of Area 11, as well as the setting of the majority of the first season. It occupies a fraction of the area of real-world Tokyo.
Dividing the concession area from the ghettos that surround it is the 5th Circinate Line of its monorail system, which takes the place of the former Yamanote Line. Militarily, its forces are organized into defense circles radiating from the Viceroy's Palace. The third such line from the center is called the Atsugi Line. Ashford Academy is located on the outskirts of the concession area. So as to provide a regular foundation for ease of construction over the ruins of Old Tokyo, the street level of the concession in fact rests upon a series of interlocked plates, which can be removed in case of earthquakes or other disasters. The locking mechanism is controlled via a closed-circuit system from a city administration facility. Lelouch twice exploits this in his battles against the Britannian army: first during the Assault on Tokyo Settlement in 2017 , where he causes the top portion of the entire structure to collapse, destroying much of Cornelia's army; and again a year later to dump a small contingent of Britannian forces onto Chinese consulate soil in order to rescue the captured members of the Black Knights. After the Second Assault on Tokyo Settlement, a majority of the concession area is obliterated by Nina Einstein's F.L.E.I.J.A.. In the ensuing chaos, the settlement's operation has been hindered with the infrastructure, effectively in shambles. A month after the battle, reconstruction work is underway.
Shinjuku Ghetto is not within the Tokyo Settlement but borders it.