Isolation of individual cells from a bulk sample is vital in cell based diagnostics. Previous work has established the ability to arrange target cells into ordered arrays, using physical barriers such as micropillars and cups [1]. We here present a magnetic separation device that allows the tagged cells of interest to align into a highly ordered array where they are selected based on both immuno-markers and size. But, unlike the physical barrier methods, our device is able to trap the cells using an only 160-nm thin film of permalloy (80% Nickel, 20% Iron) micropatterned on the base of the chamber (Fig. 1). Maxima of the magnetic field arise in the vicinity of the sharp edges of these localized micro-spots (Fig. 2), thereby creating potential wells to localize paramagnetic bioparticles such as tagged cells or beads during analysis or successive washing steps (Fig. 3). Compared to a complex network of physical barriers, the trapped cells can simply be released by turning off the external magnet, allowing for further downstream analysis or removal to waste.