Nanocellulose has enormous potential to provide an important materials platform in numerous product sectors. This study builds on previous work by the same authors in which likely high-volume, low-volume, and novel applications for cellulosic nanomaterials were identified. In particular, this study creates a transparent methodology and estimates the potential annual tonnage requirements for nanocellulose in the previously identified applications in the United States (U.S.). High, average, and low market penetration estimates are provided for each application. Published data sources of materials use in the various applications provide the basis for estimating nanocellulose market size. Annual U.S. market potential for high-volume applications of nanocellulose is estimated at 6 million metric tons, based on current markets and middle market penetration estimates. The largest uses for nanocellulose are projected to be in packaging (2.0 million metric tons), paper (1.5 million metric tons), and plastic film applications (0.7 million metric tons). Cement has a potential nanocellulose market size of over 4 million metric tons on a global basis, but the U.S. market share estimated for cement is 21,000 metric tons, assuming market pene - tration is initially limited to the ultra-high performance concrete market. Total annual consumption of nanocellulose for low-volume applications is less than 10% of the high-volume applications. Estimates for nanocellulose use in emerging novel applications were not made because these applications generally have yet to come to market. The study found that the majority of the near-term market potential for nanocellulose appears to be in its fibrillar versus crystalline form. Market size estimates exceed three prior estimates for nanocellulose applications, but the method - ologies for those studies are not transparent. Application: This work develops a methodology for estimating market volumes for nanocellulose in high-vol- ume, low-volume, and emerging sector applications and presents initial market estimates. The methodology and estimates may be used for planning and research decision making.