The United States' progression to the World Cup round of 16 was a historic achievment not only for the US (who made consecutive knockout stages for the first time), but for CONCACAF as well.
Why, you ask?
It is the first time in World Cup history that the North American region has sent three teams to the round of 16 (Mexico and Costa Rica being the others), which fits right in with the notion that this is, indeed, the World Cup of the Americas.
Of course, the sample size is relatively small here, because CONCACAF didn't even send three teams to a World Cup until France '98, after FIFA expanded the tournament field from 24 teams to 32.
CONCACAF has come close before, in 2002 – the US and Mexico advanced, but Costa Rica missed out only on goal differential after a six-goal swing on the final day of group play.