The electronic structure of a clean (110) surface of crystalline aluminum is investigated experimentally by measuring the angle-resolved ultraviolet photoemission spectra at high-symmetry points of the surface Brillouin zone for photon energies in the range 10-29 eV. The binding energies and dispersions of several features in the experimental spectra are determined. The experimental data are interpreted by means of an ab initio full-potential linear-augmented plane-wave calculation of the surface electronic structure based on density functional theory. Two of the features in the spectra are identified as being due to emission from previously unobserved surface states and surface resonances. The effects of surface relaxation on the surface electronic structure are discussed.