AbstractThe Lamprey River Hydrological Observatory (LRHO) is a lowland coastal watershed in southeastern New Hampshire (USA). The LRHO offers a platform to investigate the effects of suburbanization and changing seasonality on watershed hydrology, biogeochemistry, and nutrient export to an estuarine ecosystem. The LRHO utilizes a nested‐watershed design to examine headwater stream and main‐stem river dynamics distributed across a mixed land‐use environment. Data sets from the LRHO now comprise over 20 years of weekly grab sample data as well as 7 years of high‐frequency sensor data. Collectively these data sets include measures of discharge, dissolved organic matter, nutrients, cations and anions, greenhouse gases, and other physio‐chemical properties. Here we share information on the setting and motivating questions of the LRHO and data availability.