Electron Spin Resonance (ESR), temperature dependent Hall effect measurements and photoluminesence (PL) are used to examine the assumption that the residual donor in β-SiC films is nitrogen. At low temperatures the ESR has a three line isotropic spectrum which is characteristic of a central hyperfine interaction with nitrogen. The temperature dependence of the intensity of the nitrogen ESR signal correlates with the concentration of un-ionized donors measured by the Hall effect. Donor-Acceptor pair PL spectra are used to establish that the binding energy of the dominant donor in the films is the same as the nitrogen donor observed in Lely-grown samples. Neither PL nor ESR provide any evidence for the presence of a shallower donor.