First sewer lair (Mirage)

In the Mirage TMNT continuity, the first sewer  is the lair where raised his four adopted mutant turtle sons, ,  and  from first mutation and earliest childhood. Later, moves in after Splinter and the turtles move out, and from then on it becomes Leatherhead's lair.

History
This lair features in various TMNT stories that take place during the ' earlier lives (such as Not Forgotten), but it must be abandoned after volume 1 issue 2 when it is discovered and partially destroyed by 's. The turtles are given a new home in 's apartment in the building, and Splinter joins them later after the destruction of.

More than two years later, after having lived over a year in April's apartment and then more than another year at the, Raphael returns to New York City on his own and allies himself with , a straggler from the destruction of TCRI, who is going insane in Earth's less breathable atmosphere. Raph and Zog live temporarily in the ruins of the old lair as they prepare to attack the. Raph's brothers rejoin him and they successfully kill Oroku Saki's clone (with Zog getting killed in the process), but the family opts not to move back into their wrecked compromised first lair, and instead finds a to live in.

Later, during the events of Leatherhead, the turtles befriend Leatherhead, a mutant alligator ally of the who had been left behind when TCRI was evacuated. Leatherhead fashions a sewer lair of his own, but it is discovered and compromised by cryptid hunter, forcing Leatherhead to move. Leatherhead's new turtle friends give him the remains of their first sewer lair for him to live with, and it becomes Leatherhead's lair.

In this lair, Leatherhead gradually tries to construct a transmat device in the hopes of eventually rejoining his adoptive Utrom family on their homeworld.