This data release is a collection of data and field notes documenting snow and ice changes on South Cascade Glacier, Washington, USA. The field records relate to glaciological research and reflect evolving interpretations of glacier mass balance, climatology, hydrology, and other glacier-related research conducted at the site between 1957 to 2022 in association with the USGS Benchmark Glacier Project. Notebooks have been scanned in their entirety in PDF format. The USGS Benchmark Glacier Project has monitored targeted mountain glaciers across North America since research was initiated at South Cascade Glacier in 1957. Data from the five benchmark glaciers located in Alaska, Washington, and Montana, provide continental-scale insight into 20th century climate forcing and represent one of the longest continuous records of North American glacier mass balance. These intensively studied glaciers provide insight into the connection between climate and glaciers at multiple scales.