Let me assert that people in the United States of America have no idea what music grades or music examinations are, because we have no such system. It might be a really good idea, but we don't have one.
Please read my previous question: What are the ABRSM graded examinations, and why would one want to take them? I asked this question here two years ago because I read on this site where others were talking about "music grades" and "examinations" and I had no idea what they were referring to!
I am 50 years old, and have lived in the USA all my life. I have a bachelor's degree in music from a properly accredited university the USA, and I have been a music journalist for musicians' magazines read throughout the USA. So I was ignorant of this whole system, as I suspect are all other musicians in the USA who have not worked in other nations!
When I went looking for information about the British ABRSM exams, I found a purported USA website (put up by the British board) which listed only a small handful of teachers in a few cities in the USA who administered the British examinations to USA musicians. It appears that they are doing virtually no business with regard to giving exams.
One person on this site answered above that they believe that there are a few states within the 50 states of the USA that have an exam system comparable to the ABRSM, but they have offered no examples. I have never heard of any such system. If such systems do exist, they are not well-known and it must be that very few musicians participate in them.
I acknowledge that we in the USA are culturally quite far behind the rest of the world in matters like classical music, despite the ubiquity of the popular entertainment we create and have exported around the world in the last 100 years.
I hope I am not digressing too much, but I wish to explain why we have no such recognized "grades" or examination system:
It has to do with our national character and culture: In the United States of America, despite over 200 years of existence, we have never had any kind of national system for educational standards for children up to the age of 18 in any field. Rather, each of the 50 states and the territories in the USA have established their own independent systems and standards for education.
This changed somewhat in the year 1980, when our President, by executive order, established a national Department of Education. It is by far the smallest bureau of the USA's government and to the best of my knowledge has little or nothing to say about music education.
The reason for all this is strongly ingrained in our culture: each of the 50 states and the territories have broad authority to set their own individual laws and legal standards in many different areas of the law. Very few areas of the law are reserved for the federal, or national government. Laws and standards in any one of the 50 states can and do contradict laws and standards in the other states; any one state can ignore and refuse to enforce laws and standards which apply within the territories of each of the other states. With the citizens of each state there is an attitude of resentment and mistrust toward "intrusion" from the national government.
It is a long-established position of policy throughout our land that each individual school system, at the city or county level, and to some degree the state level, should establish their own curriculums in all school subjects, without any input from a national organization, let alone the national government.
Only since 2001 has there been a national USA government-standardized examination system for achievement in elementary school, and it only measures mathematics and reading. The most widespread manifestation of this is what we call the CRCT or Criterion-Referenced Competency Tests. It is extremely controversial and widely despised by educators throughout the nation.
Now there is a new system being promulgated in the USA, from the national level, called the Common Core system, which only provides recommendations for standard curriculum content in public schools throughout all the 50 states and territories. This is an extremely controversial development and it is being widely mocked among the citizenry. As it now stands, the Common Core system does not provide any sort of curriculum suggestions for music students.
In the USA, we do have nationally-accepted standards for high-school diplomas and for standards and recognition of university degrees in all academic fields. But the standards which are recognized nation-wide are mostly maintained by independent, non-governmental bodies and professional societies.
I should also point out that if one is a certified expert in a certain field in one state, for instance a school-teacher (working for a local-government-run school), a physician, or lawyer; one does not have the legal right to teach or practice medicine or law in any other state, as each of our 50 states and the territories have their own state government certification processes that generally do not grant recognition to practitioners in any of the other states. If you are a lawyer working in one state in the USA and you wish to move to another state and work there, you first must engage in a lengthy study of the new state's laws (sometimes lasting years) and pass certification examinations for the new state.
To citizens of other nations, the system in the USA seems bizarre, and I understand why. It is not one system. It is many independent systems that often contradict each other. But it is all in our national character.
Thanks for indulging me in this overly-long answer.