CERN Open Data Portal - Access data from CERN experiments, including those from the Large Hadron Collider.
Focus: High-energy physics
Materials Data Facility - Hosts data (some as large as several terabytes!)
Focus: Materials science
NIST Science Data Portal - Provides access to publicly available datasets encompassing various scientific disciplines.
Focus: Multidisciplinary scientific, engineering, and technological data
NASA Astrophysics Data System - A digital library portal for researchers offering access to a vast collection of scientific papers and data.
Focus: Astronomy and astrophysics
Planetary Data System - Archives and distributes scientific data from NASA's planetary missions, supporting research and analysis.
Focus: Planetary science
Earth Observing System Data and Information System - Provides access to a wide range of data from NASA's Earth Observing System. Archives hold more than 100PB of data, with 300TB of data distributed every day!
Focus: Earth science
DataONE - A community driven program providing access to data across multiple member repositories.
Focus: Earth and environmental sciences
Oak Ridge National Laboratory Distributed Active Archive Center - Archives and distributes data supporting research in Earth system science.
Focus: Biogeochemical dynamics and environmental processes
National Snow and Ice Data Center - Manages and distributes data concerning snow, ice, glaciers, frozen ground, and climate interactions.
Focus: Cryospheric
National Climatic Data Center - A large archive of climate data covering the depths of the ocean to the surface of the sun.
Focus: Environmental
EarthChem Portal - Geochemical data from a variety of sources worldwide. Advanced search interface allows users to define many parameters to find appropriate information.
Focus: Geosciences
National Geophysical Data Center - Bathymetry, earth observations from space, geomagnetic data & models, marine geology & geophysics, natural hazards, space weather & solar events.
Focus: Geosciences
ShareGeo Open - ShareGeo Open is a spatial data repository that promotes data sharing between creators and users of spatial data.
Focus: Geospatial
Pangaea - Open access data repository that archives, publishes and distributes geo-referenced data from earth system research.
Focus: Geosciences
National Geologic Map Database - Database by the USGS and the Association of American State Geologists.
Focus: Geosciences