Whenever you're talking about the location of something, you always use estar. It doesn't matter if you've just found it or not.
That said, it appears there are a few situations where "aquí es" would be correct. Example: "Está aquí el hotel" = "The hotel is here" "Es aquí el hotel" = "There is a hotel here"
The first sentence is referring to the specific location of the hotel, while the second one is more like saying that a hotel exists in this area. I got this from wordreference, and it was written by a native speaker so I guess it's correct. But I've never heard anybody say "aquí es", so the usage must be really rare. You're better off saying, "Hay hotel aquí" and avoiding the whole mess.
I thought that with geographical places the estar form would be used instead