We demonstrated the fabrication of graphene nanoribbons (GNRs) as narrow as 35 nm created using scanning probe lithography to deposit a polymer mask(1-3) and then fluorinating the sample to isolate the masked graphene from the surrounding wide band gap fluorographene. The polymer protected the GNR from atmospheric adsorbates while the adjacent fluorographene stably p-doped the GNRs which had electron mobilities of ∼2700 cm2/(V·s). Chemical isolation of the GNR enabled resetting the device to nearly pristine graphene.