Mental representations—like many other things—seem to have parts. However, it isn’t clear how to properly understand the idea of a part of a representation. In this paper I shed new light on how representations can have a mereology. In particular, it has been recognized that there is a mereological element to Kant’s distinction between two kinds of representations: intuitions and concepts. A concept depends upon its parts, whereas an intuition is prior to its parts. The paper thus focuses on an exploration of how to make sense of the parts and wholes of intuitions and concepts.