Thesis title: Girt by B: Radio Polarimetric Observations of Kiloparsec-Scale Magnetic Fields Thesis abstract: In this thesis I address some of the central questions regarding the growth of magnetic fields from the confines of galaxies into the large-scale pervasive fields observed today. Specifically, I have used radio polarisation data, acquired primarily with the Australia Telescope Compact Array, and large surveys to carry out four individual investigations into the evolution of magnetic fields on kiloparsec scales. I carry out an investigation into the magnetic field structure in the Magellanic Bridge, a nearby tidal remnant, which was conducted through the observation of Faraday rotation towards 167 polarised background radio sources. Comparing measured Faraday depth values of sources `on' and `off' the Bridge, I find that the two populations are different. Assuming that this difference in populations is due to a coherent field in the Magellanic Bridge, the observed Faraday depths indicate a median line-of-sight magnetic-field strength of B|| 0.3 G directed uniformly away from us. This is the first detection of a coherent magnetic field spanning the entirety of the Magellanic Bridge and I argue that this is a direct probe of a `pan-Magellanic' field. I present broadband polarisation observations of the radio galaxy NGC 612 (PKS B0131-637). By fitting complex polarisation models to the polarised spectrum of each pixel, I find that a single polarisation component can adequately describe the observed signal for most of the radio galaxy. I argue that the bulk of the Faraday rotation must be taking place very near, or at, the location of the polarised emission, yielding an estimated total magnetic field strength of 4 G. If the location of the bulk polarised emission is located cospatially with a coherent magnetic field, the implied thermal mass of the two lobes is of the order 109 M. I carry out a broadband polarisation investigation into the lobes of radio galaxy MSH 05-313 (ESO363 G-027). After correcting for the dominant Galactic Faraday component, I reveal gradients in the Faraday depth across the outer lobes. Using derived age estimates in conjunction with magnetic field strength estimates, I show that Kelvin-Helmholtz instabilities could serve as a plausible explanation for the observed Faraday depth patterns. I go on to argue that the thermal material responsible for the observed Faraday rotation is likely to be swept up material from the surrounding intergalactic medium. Finally, I combine the GAMA galaxy group catalogue with a large radio catalogue of rotation measures to cross-correlate galaxy group locations with the positions of known background polarised radio sources. I identify 64 instances where the line of sight to a polarised radio source passes through the angular projection of a galaxy group, but find no significant excess in residual rotation measure with respect to a number of different galaxy group parameters. Restricting the sample to radio-optical pairs with impact parameters less than the inner radius of a group, I calculate a 3 upper detection limit of B|| 2.0 G
