The Ross Ice Drainage System (RIDS) project provides a high-resolution record of atmospheric chemical deposition taken from several ice cores and snow pits located at sites within or immediately adjacent to the Ross Ice Drainage System. Three sites were visited during a 1995 traverse in inland West Antarctica. The traverse was 158 km, trending 26° from Byrd Surface Camp. The core from site A (78°44'S, 116°20'W) is 148 m deep, the core from site B (79°27.66'S, 118°02.68'W) is 60 m deep, and the core from site C (80°00.85'S, 119°33.73'W) is 60 m deep. Glaciochemical analysis focuses on the major ions deposited from the antarctic atmosphere, including Na (sodium), NH4 (ammonium), K (potassium), Mg (magnesium), Ca (calcium), Cl (chloride), NO3 (nitrate), and SO4 (sulfate). Chemical analysis also includes methanesulfonic acid (MSA) and nssSO4 (non-sea salt sulfate). The data are available by FTP in ASCII text format and Excel files.