[Formendacil]

Yes, the topographical map of Gondor, Rohan, and Mordor in the back of the Return of the King was drawn by Christopher Tolkien. So, for that matter, were the original maps included in The Fellowship and The Two Towers, until the publication of Unfinished Tales, and the redrawing of the map, which was then included in new editions of The Lord of the Rings.

J.R.R. Tolkien drew the original, rough maps that served him well as he wrote the books, but these maps were very battered, much emended, and unsuitable for publication for reasons of their coloration anyway. So he had Christopher redraw them.

However, the map in The Hobbit was done by J.R.R. Tolkien himself.