Utrom Island

In TMNT Volume 4 by Mirage Studios, Utrom Island is an artificial island created in 2002 when the alien people very publicly landed their spacecraft in Upper New York Bay near New York City. It was established as part of the Utroms' official public first contact with the inhabitants of, after their previous accidental secret first contact years before when they had operated the (TCRI) in Brooklyn using Utrom exoskeletons to conceal their identities.

The island acted as the Utroms' diplomatic mission on Earth, openly housing a local Utrom population and accepting both human and mutant visitors from the mainland. The island also had a facility, and this transmat permitted instantaneous deep space travel between Earth and other worlds. The result was an increasing exchange of contact and culture between the Earth and much of the rest of the universe using the island as a transit port. This had a beneficial effect for the Turtles, and ; considering the TCRI incident was still an embarrassing secret to the Utroms, these mutants created by that incident could plausibly claim to be aliens who came to Earth through the transmat since 2002 and could now live public lives in broad daylight.

Trivia

 * When the spacecraft landed in the bay, it accidentally crushed an old shipwreck on the bay floor.
 * The island was a strictly weapons-free zone. Since the  appeared largely identical without their weapons, the Utroms allowed them to wear  on their plastrons to tell them apart.  The Turtles had considered color-coding their bandanas instead (all their bandanas are normally red in color), but decided that would be too dorky.