Just what I was looking for! Can you give some context on this too? Like what else is about ~400 in the US?

I can't give you much context, sorry. I just shared the numbers to save others from googling.

Hacker news is 6500 globally, and 2600 in the US, if that is any kind of context.

Alexa is one of the oldest analytics companies to publicize top rankings for websites. Today was the first time I noticed they've been bought by Amazon.

You can look around their top 50, (which they are calling top 500 for the clicks) for global and country level web traffic here: https://www.alexa.com/topsites