This iron nanoparticles database contains dimers; trimers; bcc, fcc, hexagonal close-packed (hcp), simple cubic, and diamond crystalline structures. A wide range of cell parameters, as well as rattled structures, bcc-fcc and bcc-hcp transitional structures, surface slabs cleaved from relaxed bulk structures, nanoparticles and liquid configurations are included. The energy, forces and virials for the atomic structures were computed at the DFT level of theory using VASP with the PBE functional and standard PAW pseudopotentials for Fe (with 8 valence electrons, 4s^23d^6). The kinetic energy cutoff for plane waves was set to 400 eV and the energy threshold for convergence was 10-7 eV. All the DFT calculations were carried out with spin polarization.