Free Cities

The Free Cities are several powerful, independent city-states located across the Narrow Sea to the east of Westeros. They are located on the north-western coast of the massive eastern continent of Essos. They trade with the Seven Kingdoms, and each one is a distinct and individual culture by itself. Pentos is the first Free City to appear in the series.

In the books
In the Song of Ice and Fire novels there are nine Free Cities: Braavos, Pentos, Norvos, Qohor, Lorath, Tyrosh, Lys, Myr and Volantis. Lorath and Lys are located on islands off the coast, whilst Norvos and Qohor are inland. The rest are major seaports.

Aside from Braavos, the Free Cities were colonies of the mighty empire of Valyria and gained their independence after the Doom. Braavos in the far north was founded by refugees fleeing Valyrian tyranny. In terms of size, Volantis appears to be physically the largest city and maybe the most populous, but Braavos is the richest and most powerful in military terms, as well as considered as being almost impregnable due to its position on a hundred islands in the middle of a vast lagoon, unassailable by land. Lys and Myr are perpetual rivals, frequently warring over the Disputed Lands to the west of the River Rhoyne. Volantis and Tyrosh are sometimes reluctantly pulled into these wars.