A macroscopic ribbon of oriented cellulose nanofibrils bearing polyethylene glycol is fabricated by stretching the cellulose nanofibrils network structure in the hydrogel state. The covalently grafted polyethylene glycol on the nanofibril surface facilitates the alignment and compartmentalization of individual nanofibrils in the ribbon. The ribbon has ultrahigh tensile strength (576 +/- 54 MPa), modulus (32.3 +/- 5.7 GPa), high transparency, and haze.