Polarised-neutron diffraction experiments on crystals of K2FeCl5·H2O are reported. Experimental magnetic structure factors were analysed using a multipolar model for the magnetisation density on the iron and ligand atoms. Our results indicate that there exists an important spin transfer of 17% from the iron to the ligands. Also a small asphericity is observed on the Fe(III) ion due to the presence of the ligands. The hydrogen bridge, in the superexchange pathway Fe–Cl⋯(H)–O–Fe, seems to favour the spin-density transfer from the iron through the chlorine, thus enhancing the magnetic interaction.