I think this is what you are looking for:
- President
- Vice President
- Speaker of the House
- President pro tempore of the Senate
- Secretary of State
- Secretary of the Treasury
- Secretary of Defense.
- Attorney General
- Secretary of the Interior
- Secretary of Agriculture
- Secretary of Commerce
- Secretary of Labor
- Secretary of Health and Human Services
- Secretary of Housing and Urban Development
- Secretary of Transportation
- Secretary of Energy
- Secretary of Education
- Secretary of Veterans Affairs
- Secretary of Homeland Security
- Following the last position above would be the top military commander/s. (Chairman of the Joint Chiefs of Staff & Secretaries of the Army, Navy, & Air Force.)
The US Govt. does not have a "Chain of Command" because it is not a military structure. It's actually called the "Order of Succession", a government term, and is commonly confused with the Military term "Chain of Command". The Chain of Command is the line of authority and responsibility along which orders are passed within a military unit and between different units.
Example:
Army Chain of Command
- Commander-in-Chief
- Secretary of Defense
- Secretary of the Army
- Chairman, Joint Chief of Staff US Army
- Army Chief of Staff
- TRADOC Commander
- Accessions Command Commander
- Cadet Command Commander
- 4th Brigade Commander
- Sergeant Major Of The Army
- TRADOC CSM
- Accessions Command CSM
- Cadet Command CSM
- 4th Brigade CSM