What is the longest nonstop flight from the US?

Could you please elaborate on the longest nonstop flight originating from the United States? I'm curious to know which two cities are connected by this marathon journey, and what kind of aircraft is typically used for such a long haul? Additionally, how does the duration of this flight compare to other international nonstop routes? Lastly, are there any specific challenges or considerations that passengers need to be aware of when embarking on such a lengthy flight?