The results of rotationally resolved resonance enhanced multiphoton ionization photoelectron spectroscopy and zero kinetic energy-pulsed field ionization studies on HBr via various rotational levels of the F-1 Delta(2) and f(3) Delta(2) Rydberg states are reported. These studies lead to an accurate determination of the lowest ionization threshold as 94 098.9+/-1 cm(-1). Observed rotational and spin-orbit branching ratios are compared to the results of ab initio calculations. The differences between theory and experiment highlight the dominant role of rotational and spin-orbit interactions for the dynamic properties of the high-n Rydberg states involved in the pulsed field ionization process.