Latin American cities are expanding at very fast rates, amounting to an average of 20 m2 per minute. A significant portion of this new fast development is occurring at the fringe of urban areas in an informal manner, outside the planning system and standard urban planning practice. Quantifying and characterizing these new urban peripheries (NUPs) remain as large challenges. Effective methods for understanding and measuring NUPs and informal urban development are needed to support feasible solutions, establishing distance from current assessments based mostly on tenure discussions. In this paper, spatial characterizations were developed for the NUPs of three Latin American cities: Bogota, Lima and Santiago de Chile. To characterize levels of informal urban development, specific material features of urban development were analysed. The aim was to explore features of NUPs by examining the material, i.e. physical, informality of the urban tissue. The results show that NUPs follow very specific and differentiated spatial patterns, namely, compact in Bogota, irregular but attached to the urban core in Lima, and highly fragmented and diffuse in Santiago, with different material expression of informal urban development as well. NUPs are differentiated depending on territorial and local socio-economic specificities in contexts where more effective quantitative measures are needed. (C) 2016 Elsevier B.V. All rights reserved.