Disclaimer: GIS data sites move. If a site link is inactive, try searching with keywords.
Open data = data that can be freely used, re-used and redistributed by anyone
Note: not all free data are open
- Esri data housed at Wesleyan (dragon/apps/ESRI Data and Maps/)
 - Esri open data portal and Living Atlas portal
 - Connecticut DEEP data
 - UConn MAGIC
 - CT ECO
 - UConn CLEAR
 - City of Middletown (CT) data portal and interactive GIS data site and older data site
 - City of Middletown 1951 aerial photos
 - US geospatial data repository
 - US Census (To request a free data workshop, training, or presentation from the U.S. Census Bureau, please contact the Data Dissemination Office at census.askdata@census.gov or 1-844-ASK-DATA (1-844-275-3282).)
 - List of geospatial data portals
 - Western CT Council of Governments data
 - Institute for Health Metrics and Evaluation global disease data
 - New York City tax lot data (PLUTO) and geographic base map files
 - David Rumsey historical map collection
 - British Library collection of online georeferenced maps
 - National Historical Geographic Information System, free census data and compatible GIS boundary files for the United States between 1790 and 2012
 - Middletown Biodiversity Database
 - Connecticut Sanborn Maps
 - Puerto Rico GIS data portal
 - Downloadable 250m soils data for Africa
 - GeoCommunity
 - Diva GIS
 - Free GIS data
 - Geocommons
 - The Geospatial Platform: a repository of spatial data created and managed by US federal agencies
 - Climate Data:
- US data related to climate change from climate.gov
 - WorldClim
 - NCAR’s Community Climate System Model
 - GIS Resources list
 - NASA GISS Surface Temperature Analysis
 - NWS Climate Prediction Center
 - NOAA Climate Data Online
 - USGS North America Climate (derived from WorldClim)
 
 - Ecological Land Units data and maps (USGS & Esri)
 - Ecological Marine Units
 - iDigBio
 - Many US universities have data repositories or portals
 - List of 10 free data sources
 - The US Government open data site is Data.gov. Some local data is also included.
 - CT Transit data: GTFS data and plug in or shapefile
 - National Map
 - Esri geographic data portal, ArcGIS Living Atlas of the World
 - EPA data (also search the EPA archive)
 - USGS Water Resources
 - OpenStreetMap, which provides open data: you are free to use it for any purpose as long as you credit OpenStreetMap and its contributors.
 - Free GIS Data and Imagery Geoblog: http://gisdata.blogspot.com/index.html
 - Environmental Dataset Gateway
 - American Indian/Alaska Native Areas/Hawaiian Home Lands
 - J. Kerski’s list of Top 10 GIS Data Portals
 - Biodiversity data:
- https://www.gbif.org/
 - Western Association of Fish and Wildlife Agency’s Crucial Habitat Assessment Tool data, http://www.wafwachat.org/pages/west-wide-chat
 - http://aseanbiodiversity.org
 - Bay Area Conservation Lands Network
 - Nature’s Network (for the Northeast US)
 - Landscape Project (New Jersey)
 - Gap Species Richness (McKerrow et al., 2018), https://doi.org/10.1111/ddi.12779
 - Biodiversity Priority (Jenkins et al., 2015), https://doi.org/10.1073/pnas.1418034112
 - Ecosystem Representation (Aycrigg et al., 2014), https://doi.org/10.5849/jof.15-050
 - iNaturalist
 - Plantsnap
 - Global Biodiversity Information Facility (GBIF)
 - InfoAmazonia – open GIS data sets for Amazon region
 - Amazonia Socioambiental – georeferenced socio-environmental data
 
 - Ordnance Survey OpenData from Great Britain basemap collection
 - Baltic Sea maritime spatial planning relevant data
 - Open-source maps from OpenMapTiles.org
 - OpenContext.org, open research data
 - Data.gov Ocean, data, information, and decision tools related to oceans, coasts, and Great Lakes
 - GIS resources in marine sciences (Stanford Library)
 - Global impact crater GIS database
 - GPS waypoints for U.S. POIs
 - An interactive map to access open data portals across the world
 - GIS data for Mexico
 
