Hume writes that it is “no inconsiderable part of science barely to know the different operations of the mind, to separate them from each other, to class them under their proper heads, and to correct all that seeming disorder, in which they lie involved, when made the object of reflection and enquiry.” He describes this branch of knowledge as “mental geography.” Yet while his mental geography of thought is now well understood, his mental geography of feeling—specifically, of the non-sensory “secondary impressions” or “impressions of reflection” that he discusses in Books 2 and 3 of A Treatise of Human Nature—has not been. This essay seeks to clarify Hume’s doctrines in these two Books by explaining the nature and classification of the five kinds of secondary impressions that Hume distinguishes: (1) sensible agitations (i.e., “emotions” in one sense of that term); (2) feelings of or from mental operations; (3) volitions; (4) passions (both calm and violent); and (5) sentiments of taste.