Nano-sized cellulose materials has recently become topical in the sphere of sustainable materials. The two key groups of nanocelluloses (NCs) are (1) nanofibrillated cellulose (NFC) and (2) cellulose nanocrystals (CNC). They are often considered as second-generation renewable resources, which also serve as better replacements for petroleum-based products. More attention has been given to these materials because of their low density and high mechanical, renewable, and biodegradable properties. There are many works in the literature on the isolation of NFC and CNC from different sources like hard/soft wood and agriculture biomass. However, this is a comprehensive review dedicated to the properties of NFC and CNC extracted only from agriculture and industrial waste using mechanical, chemical, and enzymatic methods. This article explores in detail the importance of agriculture waste and pretreatments, methods involved in the production of nanocellulose, and the properties of NC prepared from crop and industri...