Where Federal Employees Work

From Pew Research Center, as of March 2024:

Click to enlarge for better viewing.

So it's easy to see that more than half of federal employees are in the VA (doctors, nurses, support staff) or the military. Note: These numbers shown for the various branches of the military are the civilian employees, not the active duty members of the Army, Navy, and so on.

Homeland Security (a department that's only existed as such since 9/11, and which I would argue could use some downsizing) is the next largest.

After that, Agriculture — one third of which is made up Forest Service employees — is one of the larger remaining departments. 

This chart does not include the U.S. Postal Service, which is an independent federal agency employing an additional 600,000 people. 

The chart comes from this page on the Pew Research Center site, where there is lots of other great information, such as where employees are located and salary ranges. 

Federal employment, excluding the Postal Service, "accounts for 1.5% of total civilian employment, a share that – except for a temporary bump in mid-2020 for the decennial census – has been largely constant for more than a decade." 

The Postal Service's employment numbers have declined by half since their high at the end of the 1990s. I don't  know about you, but I felt better served by the Postal Service back then.