I am not an experienced bird watcher, so for me to suddenly appear in the presence of such a beautiful bird is an amazing privilege.
I looked it up in the National Audubon Society Field Guide to Birds, Eastern Region of North America. That's it, I should be looking for the Central Region. I do not see such exact bird among the photographs.
It looks like an egret, but could be a heron? I search the Web and discover that Egret and Heron are of the same family of birds. I am looking at the Great Blue Heron in the warm Autumn sun.
This is where I found a similar bird: http://www.allaboutbirds.org/guide/Great_Blue_Heron/id