I got this because it won this year's Tiptree Award, which seems to me to put forward some reasonable challenges to the Hugo/Nebula establishment. I thought it was a very good book. The setting is a near-future Britain, underpopulated and oppressed due to climate change and war; the narrator, a woman known only as "Sister", flees her native town to join a community of women in the Lake District, and they spend the rest of the book preparing for their struggle with Authority (ie the government). This is the kind of story that is often done embarrassingly badly (see, for instance, Sherri S Tepper on occasion, or The Rising of the Moon) but Hall does it well; Carhullan is emphatically not a utopia, nor is it destined to be a permanent answer to an unjust society, and the leader Jackie and her colleagues are memorable figures. Some readers will be reminded of The Dispossessed, or The Handmaid's Tale, and I guess it's fair to say that if you didn't like either of those books The Carhullan Army will leave you cold. But actually I felt it was also perhaps a response to John Christopher's The Death of Grass, where the protagonists are engaged in essentially a selfish struggle to get through their post-apocalyptic landscape to (if I remember rightly) the Lake District; the Carhullan Army have a more altruistic and redeeming purpose.
Not surprisingly, a rather easy pass for the Bechdel test. Also in response to peake's query, the text in my edition starts on page 5 and ends on page 207, with several blank pages in between, so I reckon under 200 pages of actual story.