This question already has an answer here:
I am traveling to the USA on B-1 visa to attend a 6-day leadership program, from the 13th to the 18th of November. However, I have booked my flight tickets so that I arrive on the 6th of November and depart on 28th November. The total stay will be 23 days. The university invitation letter only states the program dates.
I have booked a room for the 6th to the 13th in Boston, will be staying in university housing during the program, and I will again book the room from the 18th to the 28th.
My question is whether is fine to stay that long on a B-1 visa. I have 10-year visa.
What will I be asked on arrival at the airport? What documents should I carry?