New Delos neighbouring systems
|X:Y Coordinates||-38.00 : -140.69[e]|
|Recharge time||198 hours|
|Recharge station(s)||Zenith, Nadir|
Note: X and Y are coordinates (light years on XY plane) relative to Terra at (0, 0)
| Jump point
|Atmospheric pressure||Standard (Breathable)|
|Equatorial temperature||42°C (Tropical)|
|Highest native life||Reptile|
|Reference Year||3025 - 3067|
|Ruler|| General Jessica Owen (3025)|
General Natalia Simonov (3067)
|Population|| 2,110,000,000 (3025)|
|HPG (Representative)||A (Precentor Bernard Ofwitz (3025))|
- 2271 - Inhabited world 
- 2596 - Free Worlds League 
- 2750 - Free Worlds League 
- 2765 - Free Worlds League 
- 2786 - Free Worlds League 
- 2822 - Free Worlds League 
- 2845 - Free Worlds League 
- 3025 - Free Worlds League 
- 3030 - Free Worlds League 
- 3040 - Free Worlds League 
- 3052 - Free Worlds League 
- 3057 - Free Worlds League 
- 3062 - Free Worlds League 
- 3067 - Free Worlds League 
- 3079 - The Protectorate 
- 3081 - The Protectorate 
- 3130 - Oriente Protectorate 
Age of War
In 2531 New Delos played host to negotiations between Captain-General Albert Marik of the Free Worlds League and Chancellor Mica Liao of the Capellan Confederation. The negotiations were instigated by Director-General Ian Cameron of the Terran Hegemony and aimed to find a peaceful resolution to the Second Andurien War, which had been raging for three years. Much to the surprise of many, a peaceful settlement was actually reached after some weeks of negotiation; a number of border resolutions were drawn up, demarcating borders clearly that had been disputed for years, and settlements were reached over a number of long-running problems. The Capellan Confederation agreed to pay an indemnity to the Free Worlds League for launching the invasion, with both sides affirming that the worlds of Andurien and Hassad were Free Worlds League property.
The Star League
In 2759, the dam on the Harlow River burst flooding the nearby city of Harlow. Hundreds of thousands of individuals were left homeless and in need of assistance. SLDF troops under the command of William Orfelt arrived and quickly help organize a relief effort to help those in need. For his efforts, William Orfelt was awarded the Hegemony Medal.
The historical and political significance of New Delos made it the perfect location for a number of trade summits between Star League member states. Delegates from the Star League, Free Worlds League and Capellan Confederation were commonly on world to attend these conferences with the SLDF providing security. During one of these summits, a plot was uncovered to sabotage the talks. The quick actions by elements of the 131st BattleMech Division eliminated the threat, but those funding the potential terrorist plot were never uncovered.
In 2762 elements of the Second Brigade of the Fusiliers of Oriente were training with the First Orloff Grenadiers when they discovered a pirate raid. The Second Fusiliers attempted to engage the pirate force, which Grand Duke Cedro Allison of the Duchy of Oriente believed to be under Maskirovka direction, when elements of the Star League Defense Force 131st BattleMech Division intervened and engaged the pirates directly. The SLDF forces - which were from the 1333rd Brigade - ended up having to surround the Second Fusiliers and order them to stand down after frustrated elements within the Fusiliers fired warning shots on the lead BattleMech company from the 1333rd.
The news that battlefield control had been removed from Major Mykonos of the Fusiliers by the 131st on the grounds that the pirate raid was Star League business, rather than internal Free Worlds League business, infuriated the Grand Duke, in part because of the SLDF refusing to intervene in the earlier Marik Civil War on the grounds that the Civil War was internal FWL business.
First Succession War
During the First Succession War the Free Worlds League captured a number of Terran Hegemony worlds before Captain-General Kenyon Marik decided to invade the Capellan Confederation. He directed ten regiments of the Marik Militia to carve a path to Sarna, which began with successful invasions of the Capellan worlds of Corey and Wazan. New Delos was a major staging base for the campaign, and was a target of a counterattack ordered by Chancellor Barbara Liao. Preparing a massive flotilla under the codename Strike Force Devlin, Barbara Liao would issue one of the most infamous orders of the First Succession War, indicating the Ares Conventions were suspended and authorising mass civilian casualties in a misguided attempt to teach the the Free Worlds League the price of striking the Confederation and bully them into retreat. Using recently captured Marik codebooks, Strike Force Devlin took the vastly outnumbered Marik defenders on New Delos by complete surprise before engaging in three days of wanton slaughter that would be later known as the New Delos Massacre. Though inflicting only relatively light damage on FWLM materiel and personnel before withdrawing, the Capellans would focus heavily on non-military targets, brutally killing over 20,000 New Delos civilians.    
In retaliation for the attack on New Delos - and to try and disrupt the flow of Capellan reinforcements to Corey and Wazan - Kenyon Marik ordered attacks on Hall, Ingersoll, New Canton and Outreach that saw the various worlds firebombed, with the attacks only stopping when FWLM forces successfully detected and routed a second attack by Strike Force Devlin against Calloway VI in 2789, putting the Capellans on the defense.  
Second Succession War
During the sixth battle for New Delos in 2845 the noted field commander Harlan Allison was killed. Harlan was the last of his line, and had led the First Fusiliers of Oriente during the desperate defense of Irian alongside Captain-General Charles Marik in early 2843.
- Iron Guard
- House Marik (The Free Worlds League), p. 158, "New Delos"
- Handbook: House Marik, p. 70 "New Delos Planet Profile"
- Handbook: House Marik, p. 16, "Free Worlds League Founding "
- Historical: Reunification War, p. 159, "Inner Sphere - 2596"
- Era Report: 2750, p. 37, "Inner Sphere - 2750"
- Historical: Liberation of Terra Volume 1, p. 11, "Inner Sphere - 2765"
- First Succession War (Source Book), p. 25, "Inner Sphere -  Map"
- Handbook: House Marik, p. 34, "Free Worlds League after First Succession War "
- First Succession War (Source Book), p. 113, "Inner Sphere -  Map"
- House Marik (The Free Worlds League), p. 35, "Driven To The Brink"
- Historical: War of 3039, p. 133, "Inner Sphere - 3040"
- Field Manual: Updates, p. 160, "Free Worlds League Deployment Table"
- Field Report: FWLM, p. 17, "FWLM Deployment Map "
- Jihad: Final Reckoning, p. 63, "Inner Sphere - March 3081"
- Map of the Inner Sphere 3130
- House Marik (The Free Worlds League), p. 18, "The Free Worlds and Terra"
- Field Manual: SLDF, p. 106, "III Corps"
- Field Manual: SLDF, p. 111, "131st BattleMech Division"
- Field Report 2765: FWLM, p. 14, "Fusiliers of Oriente"
- Field Report 2765: FWLM, p. 5, "Internal Matters"
- House Marik (The Free Worlds League), p. 28-29, "The Collapse of Terra"
- Handbook: House Liao, p. 27 "History of the Nation - Dawn of the Succession Wars - New Delos"
- House Liao (The Capellan Confederation), pp. 45-47 "History - The Succession Wars - First Succession Wars - Blow and Counterblow"
- House Marik (The Free Worlds League), p. 34-35, "Driven To The Brink"
- Field Report 2765: FWLM, p. 19, "Regimental Status"
- First Succession War (Source Book), p. 138, "First Succession War Deployment Table - FWLM"
- Field Report: FWLM, p. 13, "Minor Provinces"
- Field Manual: 3085, p. 92, "Deployment Table - 3085"
- Era Report: 2750
- Field Manual: 3085
- Field Manual: SLDF
- Field Manual: Updates
- Field Report: FWLM
- Field Report 2765: FWLM
- First Succession War
- Handbook: House Liao
- Handbook: House Marik
- Historical: Liberation of Terra Volume 1
- Historical: Reunification War
- Historical: War of 3039
- House Liao (The Capellan Confederation)
- House Marik (The Free Worlds League)
- Jihad: Final Reckoning
- Map of the Inner Sphere 3130