We present polarization profiles of 24 pulsars observed with the Green Bank Telescope by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) timing project at 820 MHz and 1500 MHz. The profiles are calibrated using observations of B1929+10 and J1022+1001, which are used to make Mueller matrix solutions. For each pulsar we fit a rotation measure and using these rotation measures, we are able to map the Galactic magnetic field and observe how it changes over time. We fit for trends in the rotation measure, dispersion measure, and Galactic magnetic field and find that we detect small variations in magnetic fields along the line of sight to some pulsars. We discuss the polarization profiles, which can be used to constrain pulsar emission geometry, and also present the discovery of very low intensity average profile components (“microcomponents”) in five pulsars.