Electron diffraction and high-resolution electron microscopy of LaMnO3-δ (0 ≤ δ ≤ 0.25), obtained by topotactic reduction of LaMnO3, shows that an ordered pathway of anionic vacancies is only obtained for δ = 0.25. La4Mn4O11 is an eightfold superlattice of the perovskite-type structure due to the ordered intergrowth of three octahedral layers and one tetrahedral layer along the b axis, according to the sequence ...OOOTOOOT‘... The reduced sample exhibits ferromagnetic behavior with Tc ≈ 50 K. The staircase effect, observed at low temperature, is discussed in terms of the magnetic ordering adopted in the octahedral layers.