AbstractAn extensive first‐principles and atomistic Monte Carlo study on isolated Fe ( = F, Cl, Br, I) nanowires is presented. The structural properties of the Fe chains are determined and compared with their bulk structures. The results indicate that in the lowest energy configuration, the wires crystalize in a system that belongs to the space group (No. 131, Z = 2, point group ), with antiferromagnetic arrangement. The stability is determined by calculating the phonon frequencies in the whole Brillouin zone within the supercell approach. The relative stability of the periodic chains is also determined by calculating the elastic properties and comparing them with bulk cases. The band structure, the density of states, the magnetic properties, the anisotropy energy, and topological analysis, performed with the Quantum Theory of Atoms in Molecules approach, are also reported and discussed. The results support the idea that these Fe nanowire systems are promising materials for practical applications, like lithium‐ion batteries.