Last Saturday I saw this arachnid on a tree in the park near my house. It was about 2 m above the ground next to a large cavity, which was probably its hideout.
It's not possible to judge its size without a scale. Here is a picture of it with a ruler I was able to bring near it without making it run away. Its body was about 2.5 cm long.
It may have been the largest spider I have seen outside a zoo. Here is a close-up of the head.
I have posted another picture on BugGuide.Net. Hopefully, somebody will put a name on it.