Originally Answered: Is the FE and PE valid throughout the United States?
The FE is recognized in every state and US territory. If you pass the FE exam in, say, Guam, you can apply for license in any other state, provided you meet the work experience requirements.
With the PE, it's different. The PE exam, administered by NCEES, is the same in every state; you may even sit for an exam in one state while applying for a licence in another. States, however, are free to impose additional requirements. Many states require applicants to pass the Engineering Law and Ethics exam in addition to the PE. Civil Engineering applicants in California, in addition the Law and Ethics, which everyone has to pass, also have to pass Surveying and Seismic exams.
Once you have a Professional Engineer licence you can only practice Engineering in the state that issued your licence. So, if you have PE in Georgia, you cannot practice engineering in Tennessee, or New York, or Florida or any other state or US Territory. Some states can theoretically go after you for passing around your business cards with the P.E. initials after your name if you don't have a licence in that state.
You can apply for a licence in another state by reciprocity. You won't have to take the PE exam again, but you will have to satisfy the additional requirements the state imposes on the applicants.
If you're planning to practice Engineering in many states you may apply for a Model PE status from the NCEES which will confirm your credentials to any state that you apply for a licence. This makes getting the licences in other states easier.
Additionally, many states require Professional Engineers to meet the continuing education requirements. These requirements vary widely state to state; classes approved for Continuing Education Credits in one state may not necessarily be approved in another. You must satisfy the Continuing Education requirements in every state where you have your licence.
Until about 20 years ago some states granted Professional Engineer licences via the Experience and Evaluation process. I believe Vermont was one of the last ones to do so. I have a distant relative who got his PE that way in 1996; it so happens that his VT PE licence number is only a few numbers from mine. The licences granted this way, however, are not "portable," other states will not recognize them when applying for reciprocity.
I passed the FE exam in 1989 in New York. In 1994, when I applied sit for a PE in Vermont I attached a copy of my NY EIT Certificate to my application. I got my Vermont PE licence in the Summer of 1996 and immediately applied for a New York licence, which I got in the fall of that year.