This is a sequel to [25] and [30]. Associated with G := GL n and its rational representation (Ο, M ) over an algebraically closed filed k, we define an enhanced algebraic group G := G β Ο M which is a product variety GL n Γ M , endowed with an enhanced cross product. In this paper, we first show that the nilpotent cone N := N(g) of the enhanced Lie algebra g := Lie(G) has finite nilpotent orbits under adjoint G-action if and only if up to tensors with one-dimensional modules, M is isomorphic to one of the three kinds of modules: (i) a one-dimensional module, (ii) the natural module k n , (iii) the linear dual of k n when n > 2; and M is an irreducible module of dimension not bigger than 3 when n = 2. We then investigate the geometry of enhanced nilpotent orbits when the finiteness occurs. Our focus is on the enhanced group G = GL(V ) β Ξ· V with the natural representation (Ξ·, V ) of GL(V ), for which we give a precise classification of finite nilpotent orbits via a finite set e P n of so-called enhanced partitions of n = dim V , then give a precise description of the closures of enhanced nilpotent orbits via constructing so-called enhanced flag varieties. Finally, the G-equivariant intersection cohomology decomposition on the nilpotent cone of g along the closures of nilpotent orbits is established.