We have studied the crystal and magnetic structures of Fe-doped hexagonal manganites LuMn1-xFexO3(x=0,0.1,0.2, and 0.3) by using bulk magnetization and neutron powder diffraction methods. The samples crystalize consistently in a hexagonal structure and maintain the space group P63cm from 2 to 300 K. The Néel temperature TN increases continuously with increasing Fe doping. In contrast to a single G4 representation in LuMnO3, the magnetic ground state of the Fe-doped samples can only be described with a combination of Γ³(P63′cm′) and Γ4(P63′c′m) irreducible representations, whose contributions have been quantitatively estimated. The drastic effect of Fe doping is highlighted by composition-dependent spin reorientations. A phase diagram of the entire composition series is proposed based on the present result and those reported in literature. Our result demonstrates the importance of tailoring compositions in increasing magnetic transition temperatures of multiferroic systems. [ABSTRACT FROM AUTHOR]