The aim of this work was to compare the physical and chemical properties of cellulose nanowhiskers extracted from industrial bio-residue (CNW-BR) by homogenization, and microcrystalline cellulose (CNW-MCC) by acid hydrolysis. CNW-MCC showed a higher surface charge than CNW-BR when analyzed using conductometric titration. Both CNW-suspensions showed flow birefringence, indicating the presence of individualized whiskers. Morphology study confirmed that the whisker diameters were less than 10 nm for both materials, and atomic force microscope images showed somewhat more aggregated BR nanowhiskers. UV/Vis spectroscopy of the CNW-films showed transparency in visual light. The relative crystallinity obtained from X-ray diffraction was 77% for the CNW-BR, and 85% for the CNW-MCC. It was demonstrated, by thermal analysis, that the CNW-BR was more thermally stable than the CNW-MCC, having a higher degradation onset temperature (218 °C and 155 °C) as well as maximum degradation temperature.