That would be Everglades Nat’l Park’s Shark River Slough.
It is a slough!
A slough is sort of like a river, but without a channel, or rather a very wide channel, and filled with grass, or a special type of grass, called saw grass, which actually isn’t a grass at all, but rather a sedge, and either way its more than just a monoculture of Cladium jamaicense (as the botanists call it), but rather an assemblage of subtropical wetland flora.
Sort of but it flows, in a broad expanse of water called sheet flow through an aquatic labyrinth of Lilipution mountains and valleys that we call the ridge and slough landscape, which is also punctuated by bay heads, tree islands, and occasional cypress domes and pine uplands on its outskirts.

Suffice it to say that there is no place quite like it – or as Marjorie Stoneham Douglas would say – “There is only one Everglades” … even if on a recent trip to Belgium I was struck by he similarity of their High Fens (Hautes Fagnes) to Florida’s famed flowing marsh, (or was I just homesick)?