We present our attempts to detect magnetic fields in filamentary large-scale structure (LSS) by observing polarized synchrotron emission emitted by structure formation shocks. Little is known about the strength and order of magnetic fields beyond the largest clusters of galaxies, and synchrotron emission holds enormous promise as a means of probing magnetic fields in these low density regions. We’ll report on observations taken at the Green Bank Telescope, the WSRT, and polarized emission in the NVSS which reveal new Mpc scale synchrotron emission in LSS. We also highlight the major obstacle that diffuse galactic foreground emission poses for any search for large-scale, low surface-brightness extragalactic emission. We explore cross-correlation of diffuse radio emission with optical tracers of LSS as a means to statistically detecting the presence of magnetic fields in the low-density regions of the cosmic web.