Philadelphia is home to the first federal structure commissioned by the u.s. government. which was it?

U.S. Mint

The U. S. Mint

It depends on which local government you are talking about. Some cities and counties have been around since long before the revolution. Some were created last year.

The U.S. Government is called a Federal Government because it is at the Federal (or highest) Level, there is no other government above it.

the first continental congress