In Star Trek, a neutral zone is defined as a ‘buffer’ zone, where no political power holds any authority. It is typically the space between the boundaries of the colonies that have agreed to set up the zone. It is similar to the Demilitarized Zone that exists between the United Federation of Planets and the Cardassian Union in the Alpha Quadrant, which is formed according to the terms of the Federation-Cardassian Treaty of 2370.
Other notable examples include the Romulan Neutral Zone and the Klingon Neutral Zone. While any incursion into these zones is considered a hostile act, occasional breaches still occur throughout their existence. Here's what Star Trek audiences need to know about these areas of space.
Romulan Neutral Zone
The Romulan Neutral Zone in the Beta Quadrant is situated between the Federation and the Romulan Star Empire. After the conclusion of the Earth-Romulan War in 2160, the two sides negotiated a treaty. In accordance with this treaty, the Neutral Zone was established. Any entry into the zone by either party is considered an act of war. The terms of the treaty state that the Romulans have the right to take control of any of Starfleet’s ships that cross its threshold. Eight Earth Outpost Stations were built on asteroids in Sector Z-6 (along with its nearby sectors), allowing the Federation to monitor any activity on its side of the Neutral Zone.
However, in 2266, four of these border outposts and their asteroids were completely destroyed by a T'Liss-class Romulan Bird-of-Prey. The Romulans had been using the Neutral Zone to test new technology and tactical weapons, like cloaking technology (which prevented the Federation from detecting them) and plasma torpedoes, in order to provoke a response from the other side. The USS Enterprise pursued the vessel (without crossing into the Neutral Zone), until the Romulan commander finally self-destructed his ship. This marked the end of about a century since the Romulans had gone into isolation.
In 2311, there was a confrontation between the Federation and the Romulan Empire, called the ‘Tomed Incident.’ The Romulan warbird Tomed of Ivarix-class crashed into a Federation base. The resulting explosion destroyed thirteen Starfleet outposts as well as the USS Agamemnon. Led to believe that thousands had been killed, the Romulans were forced to stand down and the Treaty of Algeron was signed. The Neutral Zone is reinforced, and the Federation is banned from researching or using any cloaking device. The Romulans refrain from taking part in any interstellar politics in the next 53 years.
A number of outposts near the Neutral Zone were demolished once again in 2364. The Federation and the Romulans each believed that the other had caused the damage. However, after coming across similar attacks on other stations, it was discovered that the Borg are behind the destruction.
In 2366, the Romulan Admiral Alidar Jarok unknowingly provided false information to the Federation about a possible new base at Nelvana III, in an attempt to make the Enterprise-D enter the Neutral Zone. Even though the Romulans succeeded in their plan, a large-scale conflict was avoided in the end.
However, the Romulans attempted to deceive the Federation again in the following year by creating a false holographic future for Commander William T. Riker. Riker was tricked into believing that he is now the captain of the Enterprise, and about to negotiate a peace treaty with the Romulans. The objective was to make him reveal the location of a key Federation outpost. However, Riker suspected the truth and managed to escape. In 2369, the Federation increased defensive measures by installing granitic sensor nets and subspace listening posts on their side to detect any cloaked ships in the Neutral Zone.
In 2374, the Romulans hijacked the USS Prometheus and headed towards the Neutral Zone, but The Doctor of the USS Voyager managed to reclaim the ship mid-way. Later that year, the USS Cairo was assigned to patrol the Neutral Zone during the Dominion War, but the ship is believed to have eventually been taken over by the Dominion forces, who strike from the Romulans’ side of the zone. In 2380, the USS Cerritos sends a team through the Neutral Zone to rescue Imperium Magistrate Clar from the Romulans.
Although it was never officially dissolved, the Romulan Neutral Zone collapsed in 2387, when the supernova of the Romulan sun destroyed Romulus. By 2399, it has been partially replaced by the Romulan Free State. Refugee settlements grow within and on either side of the zone, establishing trade and commerce. The vigilantes Fenris Rangers also set up their establishment here. Both the Romulans and the Federation have limited interest in the Neutral Zone from then onwards, unless there is a potential security threat.
Federation Neutral Zone
The Klingon Neutral Zone (referred to as the “Federation Neutral Zone” by the Klingons) exists along the Federation-Klingon border in the Alpha and Beta Quadrants. It was set up in 2267, after the Organians enforced the Treaty of Organia upon the Federation and the Klingons, ending the Federation-Klingon War in 2267.
Before the Khitomer Conference in 2293, both parties considered shifting all the space stations and starbases along the Neutral Zone. Eventually, they both sign the Khitomer Accords, abolishing the zone and establishing peace for almost the next 100 years. Captain Kirk admits later on that he was extremely apprehensive of the idea of having no Neutral Zone separating them from the Klingon Empire.