Man. This is exactly why I came here. The US Holidays calendar used to be the traditional US observed holiday/celebrations. I get that the world is smaller now, but if my calendar had every global celebration, I wouldn't have room for anything else.
That said, this is what you are looking for: http://www.everythingicafe.com/add-us-holidays-calendar-iphone-ipad/
Remove/unsubscribe from all the holiday calendars you have ('on my mac', iCloud, gmail, etc.), go to Calendars on your iOS device, click Calendars at the bottom of the screen, and uncheck the US Holidays under OTHER (it's built in, you can't remove/delete it).
Then subscribe to webcal://files.apple.com/calendars/US32Holidays.ics with iCloud. This calendar has the traditional US holidays many are looking for.