Real World article
(written from a Production point of view)

According to the script for Star Trek IV: The Voyage Home, there was a peace pact between Argus and Rigel IV. A significant legal precedent originated from this pact, which was, "All beings may not be created equal yet shall be given equal opportunity and treatment under the law." In 2286, in a session of memory test, one of the questions Spock answered was about this peace pact and its legal precedent.

It might correspond to one of several places named Argus.