Who is the King in The Hobbit?

[The Saucepan Man]

In the second chapter of The Hobbit, Roast Mutton, when Bilbo and the Dwarves are debating whether to make for the light they can see, the following is said:

The old maps are no use: things have changed for the worse and the road is unguarded. They have seldom even heard of the king round here, and the less inquisitive you are as you go along, the less trouble you are likely to find.

Now, this suggests that there was a kingdom in the vicinity (the Trollshaws, just west of Rivendell). But, since the last King of Arnor had died some 1000 years earlier, and there were no other kingdoms in the vicinity, what "king" is being referred to here?