The Harrow Marsh is not covered in Cities of the Sun, and is poorly
covered in the maps too, probably due to space limits and the assumption no
sensible PC would go there. [Guess what my current goal is.] However, The
Khinasi map does show the province lines to some extent, without naming them.
In general Blood Enemies should be considered an inferior source since
much of it is written from a PC view, rather than DM. However, it is usually
superior to silence, and in the case of the Harrow Marsh, it's data should be
Lurker Above