This paper presents the first investigation on square hole-flanging produced by single point incremental forming. The aim and objective is to provide readers with a broad understanding on the deformation mechanics of the process that will enable them to understand plastic flow resulting from the interaction between the tool and the blank, to identify the influence of the pre-cut geometry in the overall formability, and to characterize the physics of failure. The methodology comprises the mechanical characterization of the material, the use of circle grid analysis, and the fabrication of square flanges with round corners by multistage single point incremental forming using blanks with different pre-cut hole geometries. The investigation is performed in aluminium AA1050-H111 and the overall results widens and enhances current research work in hole-flanging of cylindrical parts by giving the first contribution towards the understanding of plastic flow and failure in hole-flanging of square parts produced by single point incremental forming.