How do you identify who owns territory on the map in Civilization V?
Hover the mouse pointer over the tile you are interested in. After a couple of seconds a popup will appear over the tile, and it will include a line in the form of "owned by England".
So in effect there are two separate "tile information" windows - the one which appears immediately in the bottom-right, and another which appears over the tile itself after hovering. Confusing indeed :)