The Treaty of Alpha Trianguli was a treaty, ratified in late 2160 or early 2161, between United Earth and the Romulan Star Empire that ended the Earth-Romulan War.
- While the text of the treaty is in the Star Fleet Technical Manual, it is unnamed there.
It was negotiated by subspace radio between the two powers. (TOS novel: The Romulan Way, Star Trek: Avenger: "The Essential Process")