This report provides detailed information about state-legal cannabis production and sales in Washington, as well as insights about the total amount of tetrahydrocannabinol (THC) obtained from legal and illegal sources by Washington residents. Using data from Washington's traceability system, the authors estimate that approximately 26 metric tons (MT) of THC were sold in licensed retail stores in Washington from July 1, 2016, through June 30, 2017. About 18 MT were from flower, 6 MT from extracts for inhalation, and the remaining 1–2 MT from other products. This 26 MT is more than double the amount of THC sold in licensed stores in the previous year. Calculating the total amount of THC obtained by residents via legal and illegal sources is difficult with existing data sources, but using additional data from the National Survey on Drug Use and Health and a survey of cannabis users in Washington, author calculations suggest that in the third year after implementing a regulatory system for cannabis, between 40 percent and 60 percent of THC obtained by state residents was likely purchased in Washington's state-licensed stores. Learning more about why some residents are still obtaining cannabis products through other channels, what share of legal sales are to nonresidents, and the efficiency of various cannabis products at delivering THC and other cannabinoids would be fruitful areas for future analysis.