Nanostructural analysis of pillared clay samples using high-resolution transmission electron microscopy has been developed. Montmorillonite samples were pillared using partially hydrolyzed Al and Fe solutions. Two samples, M01 and M05, corresponding to Fe/(Fe+Al) ratios of 0.1 and 0.5, respectively, were analyzed. The different steps of image filtration, resulting from filtration by ring-shaped masks, are illustrated and discussed from lattice imaging of sample M01. This procedure is used to show the heterogeneous distribution of the basal spacings in the different ordered domains. Domains of mesoporosity and distribution of the different Fe species are studied specifically in the sample M05. The quantitative HRTEM results are discussed and compared with X-ray diffraction patterns obtained from the same sample.