We discuss the n electronic states of a graphite sheet which has topological defects or edges on a nanometer scale. The former is the case that pairs of pentagonal and heptagonal rings are introduced in the hexagonal network of a graphite sheet. In the latter case, we take notice of nanographite, which is a kind of graphite fragment of a nanometer size. Through the whole, we demonstrate how the π electronic states vary under the control of the nanometer topology of the three-coordinated π-electron network in a graphite sheet.