Ab initio UHF, MP2 and MP4 calculations were used to study the geometries, the electronic structure and the thermochemical stabilities of the gas phase anionic clusters of hydrogen fluoride that carry a single excess electron. Basis sets up to the aug-cc-pVDZ set were employed. These were augmented with a six or seven term even tempered (sp) cavity set. The thermochemical stabilities of these complexes against vertical ionization as well as dissociation to various products were determined. The integrated electron densities as well as the natural bond analysis revealed that a significant portion of the excess electron density is localized in the cavity region interior to the hydrogen atoms of the inner shell. Cavity orbitals had a nominal effect on the properties of the complexes and effected the prediction of the geometrical features of the complexes more than their stability.