Spartan-III Alpha company was the first of three Spartan-III companies to be recruited, trained, and put into service.

The Battle of Jericho VII was a three-day naval and ground battle pitting the UNSC versus the Covenant forces in the Lambda Serpentis system.

The Battle of New Harmony was an assault on the colony New Harmony by Covenant forces in early 2537.

The Battle of New Constantinople was a large conflict between UNSC and Covenant forces that took place some time in early 2537 on the colony of New Constantinople.

Operation: PROMETHEUS was an assault on a Covenant shipyard located on and around asteroid K7-49 by Spartan-III Alpha Company.

Spartan-III Beta company was the second of three Spartan-III companies to be recruited, trained, and put into service.

Spartan-III Gamma Company was the last of three Spartan-III companies to be recruited, trained, and put into service.

The Fall of Reach was possibly the largest battle during the Human-Covenant War, taking place in the Epsilon Eridani system, in orbit and on the ground of Reach, humanity's largest military stronghold.

The Battle of Tribute was a large-scale invasion of the colony world Tribute in the Epsilon Eridani system by Covenant forces during and after the Fall of Reach in 2552.

The Onyx Conflict was a major engagement between UNSC, Covenant, and Forerunner forces on and around the planet of Onyx in the Zeta Doradus system in October and November 2552.

Operation: JOVIAN WHISTLE was an operation executed by the UNSC 717th Xeno-Materials Exploitation Battalion to recover a Forerunner ancilla on the human colony world of Gao in the Cordoba system in the early summer 2553.