List of the 11 Kingdoms and their Modern Counterparts

This rhyme is at the front of "Camber of Culdi", and is attributed to the Lord Llewellyn.

Now, these are the Names of the Eleven Kingdoms,
sung rightly well of old:
Howicce, and Llannedd, and fierce Connait;
mountainous Meara, the Land Beyond the River;
and Kheldour, the windswept;
and pastoral Eastmarch;
Tolan, and Torenth, and myth-ridden Mooryn;
and lost Caeriesse, which sank beneath the sea;
and far-reaching Gwynedd, seat of the Haldane Kings.

Lay of the Lord Llewellyn
--Troubadour to the High King of Mooryn

Tolan, Torenth, Caeriesse, Gwynedd, Howicce, Llanedd, Connait, these are all pretty straightward. (It should be noted that the Duchy of Haldane is a part of the Kingdom of Gwynedd. However, a cursory summary of the history of Gwynedd's founding would seem to indicate that the Haldane duchy was, among several other pieces of land, a precursor to Gwynedd rather than absorbed by it.)

Mooryn is the original land now comprised of Corwyn and Carthmoor.

Meara became Cassan, Kierney, and what's now called Meara.

Kheldour became the Duchy of Claibourne and the Earldom of Rhendall. The Earldom of Rhendall, like the Earldom of Kierney's relationship with Cassan, is held by the heir of the Duke of Claibourne. Also a product of this splitting was the Kheldish Riding, held directly as a Crown territory (I believe).

And Eastmarch became Eastmarch and Marley.