England is obvious. So too Japan, and China, and Egypt. But there have been a lot of Civilization games featuring a lot of civilisations, so let's take a look at a map (made by sirprizes) showing every nation that has made it into the series and those who, sadly, have not.
You want to pay closer attention to the red nations. They're the ones who have, in some form or another (whether on their own or as part of a fallen empire) been directly represented by a playable Civ. The yellow ones have kinda been represented, but only with Civ V's city states (so for example while Australia hasn't ever officially featured as a Civ, Sydney does appear as a city state).
In some cases, whether through a complicated history, occupation or politics, there's stuff you could object to if you tried to project ancient empires (or even more recent ones, like Imperial Russia) onto modern populations. Places like Mexico are very different today to when they were represented in the game.
But those are arguments for armchair historians and Civ fanatics. For the rest of us, this is a pretty cool map, and one that shows the team has done a pretty good job of making sure all corners of the globe are represented in the games.