Powder River rises in the Bighorn Mountains of Wyoming and flows northward through a semi-arid landscape in Wyoming and Montana to the Yellowstone River. The river drains an area of 34,700 square kilometers and has an average discharge of about 500 million cubic meters per year. Cross-channel profile data were collected at 22 sites on the river and its tributaries from 1975 through 2019. Many policymakers are hoping to use this long-term data to better capture environmental and hydrological trends in the riverbed environment and predict and plan for possible changes in the river’s health, reliability, and sustainability footprint.