Magnetic fields are present throughout the Universe and many astrophysical processes are influenced by their presence. One of the largely unknown aspects of cosmic magnetism is that of the cosmic web and how magnetic fields behave in large scale structure. Due to the indirect nature of the detection of these fields, it is difficult to determine much about the origin and evolution of magnetic fields. One method of detection is to measure how the polarisation angle of light is rotated in the presence of electrons and a magnetic field. In this paper, we simulate the Rotation Measure (RM) experienced by radio emission as it travels from an extragalactic source to the observer in large-scale simulations. Our aim is to investigate the effect of extragalactic magnetic fields on the spatial distribution of RM. This paper aims to produce RM maps of the simulated universe and use these to inform upcoming radio surveys and how we can use observations to investigate the cosmic web.