This data release contains water-quality and discharge data collected at seven stream sites and one groundwater spring in Rocky Mountain National Park (RMNP), Colorado by the U.S. Geological Survey (USGS) from 10/1/2010 to 9/30/2019 using in-situ sensors and field meters. Data were collected for the purpose of quantifying downstream transport of aquatic carbon and exchange fluxes of dissolved carbon dioxide (CO₂) from streams. Parameters include daily mean discharge, dissolved CO₂, water temperature, atmospheric pressure, dissolved oxygen, fluorescent dissolved organic matter (fDOM), nitrate, specific conductance, turbidity, and corrected fDOM from 10/1/2010 to 9/30/2019 (DailyData.csv). Hourly mean dissolved CO₂, CO₂ partial pressure (pCO₂), water temperature, atmospheric pressure, dissolved oxygen, fDOM, nitrate, specific conductance, turbidity, and corrected fDOM are presented from 10/1/2016 to 9/30/2017 at one of the stream sites (AndrewsHourlyData.csv). Water temperature, turbidity, specific conductance, fDOM, corrected fDOM, and discharge values measured at 10–15-minute intervals are presented from 4/27/2011 to 9/30/2017 at two stream sites (UV_data_NandEinlets.csv). Discrete measurements of dissolved CO₂ are presented for hyporheic samples collected at one site during 2000 (AndrewsHyporheicData.csv) and for a synoptic survey of groundwater springs conducted during summer 2018 (SpringsData.csv). First posted June 17, 2021 Revised December 17, 2021 Revised October 11, 2023