What is the hierarchy among the US military branches?

In terms of ranking and responsibility, how are the different branches of the US military structured? I'm looking to understand the hierarchy among different branches like the Army, Navy, Marines, Air Force, and Coast Guard.

In the United States, the different branches of the military - the Army, Navy, Air Force, Marines, Coast Guard, and Space Force - do not operate within a strict hierarchy. Instead, their roles and responsibilities are distinct and exist concurrently. Each is structured around its own specific mission within the wider defense activities of the nation.

1. The Army will deal primarily with land-based operations. It's the oldest US military branch and was established before the country was officially formed, in June 1775. It bears the responsibility of defending the nation on the ground and protecting its boundaries against any foreign powers.

2. The Navy focuses on maritime operations. Established in October 1775, its role encompasses maintaining the freedom of the seas, securing key maritime regions, power projection (ability to deploy and sustain forces wherever they are needed), and nuclear deterrence.

3. The Marine Corps, which is technically part of the Department of the Navy, concentrates on amphibious warfare. Established in November 1775, Marines are mission-ready and often are the first boots on the ground in a conflict.

4. The Air Force, established as a separate branch in September 1947, engages in aerial warfare. Its responsibilities include air defense, space control, and global strike capabilities.

5. The Coast Guard, which falls under the Department of Homeland Security in peacetime and can be transferred to the Navy under an official declaration of war, is responsible for maritime law enforcement, marine environmental protection, and search and rescue operations.

6. The Space Force, launched in December 2019, is tasked to protect U.S. and allied interests in space, including monitoring ballistic missile launches, tracking space debris, and maintaining satellites for military communications.

To make it easier to coordinate across branches in times of joint operations, the United States has a system called the Unified Command Plan, which establishes combatant commands with a chain of command going directly from the President and Secretary of Defense to the combatant commanders of the various obligations, regardless of which branches' troops they are commanding.

However, the order of precedence, which signifies the order in which the services march in parades or official events, usually is Army (since it's the oldest), Marines, Navy, Air Force, and Coast Guard. With recent addition, Space Force, might take the last place.

Understandably it can seem complicated, but each branch plays a key role in the defense and security of the country, specializing in different fields to ensure comprehensive protection against any threats.