ArcGIS Online hosts maps and data that can be used in ArcGIS clients.
Atlas of the Biosphere : Center for Sustainability and the Global Environment (SAGE)
“The idea behind this website is simple: gather as much information about the environment as possible, and deliver it to as many people as possible. We are dedicated to bringing environmental information to the widest possible audience. Although we specifically target high school to university students and teachers, anyone can benefit from a stroll through our collection”.
Atlas of Historical County Boundaries
The Atlas of Historical County Boundaries is meant to be a resource for people seeking records of past events, and people trying to analyze, interpret and display county-based historical data like returns of elections and censuses, and for people working on state and local history projects. The special interests of those potential users range from history to demography, economics, genealogy, geography, law, and politics. While many of these goals can be achieved using the Atlas’ Interactive Maps, the downloadable data can be used with various GIS (Geographic Information Systems) programs to create specialized projects.
Bureau of Labor (U.S) (Data)
Census Bureau TIGER and TIGER/Line Mapping Center
Topologically Integrated Geographic Encoding and Referencing (TIGER) product information from the US Census Bureau, including up-to-date U.S. Census boundary shapefiles and relationship files.
Census Bureau “On The Map” – Employment and Worker Statistics/Maps
OnTheMap Version 6 is the sixth generation of OnTheMap, a web-based mapping and reporting application that shows where workers are employed and where they live. It also provides companion reports on age, earnings, industry distributions, race, ethnicity, educational attainment, and sex.
Cropland Data Layer (USDA)
The Spatial Analysis Research Section released the 2009 Cropland Data Layer (CDL) for ALL Continental US States. All state products were issued in unsmoothed format, with the exception of Florida (i.e., citrus smoothing applied) with associated metadata. The file sizes are quite large and range between 13 – 100 megabytes per download.
DATA.GOV (Tabular and Statistical data from federal agencies)
Economic Data Resources: USDA ERS
ERS’s highly trained economists and social scientists conduct research, analyze food and commodity markets, produce policy studies, and develop economic and statistical indicators. The agency’s research program is aimed at the information needs of USDA, other public policy officials, and the research community. ERS information and analysis is also used by the media, trade associations, public interest groups, and the general public. “The Agency’s work is structured among four Divisions:”
ELEVATION DATA: United States Interagency Elevation Inventory
The U.S. Interagency Elevation Inventory displays high-accuracy topographic and bathymetric data for the United States and its territories. The project is a collaborative effort between NOAA and the U.S. Geological Survey, with contributions from the Federal Emergency Management Agency. This resource is a comprehensive, nationwide listing of known high-accuracy topographic data, including lidar and IfSAR, and bathymetric data, including NOAA hydrographic surveys, multibeam data, and bathymetric lidar. This inventory was completed May 2012 and will be updated annually.
The information provided for each elevation dataset includes many attributes such as vertical accuracy, point spacing, and date of collection. A direct link to access the data or information about the contact organization is also available through the inventory.
EPA Smart Location Database: A National Dataset for Characterizing Accessibility and the Built Environment at the Neighborhood Scale
A large body of research has demonstrated that land use and the built environment can have a significant effect on travel behavior. An EPA-funded meta-analysis of this literature, “Travel and the Built Environment”, summarized the measurable effects of built environment variables on residents’ travel behavior. It found that driving is most strongly related to measures of destination accessibility and street network design, while walking is most strongly related to measures of land use diversity, intersection density, and the number of destinations within walking distance.
These findings can help to inform travel demand studies as well as land use scenario impact analysis. However developing data about these built environment characteristics can be expensive and time consuming. EPA’s Smart Location Database makes such data more widely accessible.
ESRI Basemap data:
Historic data located in the Map Library on DVD, current ESRI data is loaded onto the server in Science Hall and can be accesed from public computers.
FEMA Map Service Center
Flood Rate Insurance Maps [FIRMs] on the Web
Forest Service Geospatial Clearinghouse (USFS)
Raster and vector forest data, state and private forestry assessment data, maps, etc.
Geospatial Data Gateway
USDA Natural Resources Conservation Service. This site includes county and state level data, including but not limited to: DRGs, DEMs, census data, land cover, quad indexes, digital orthophotos, etc.
The GIS Data Depot
(GeoCommunity Data Clearinghouse) Available data include DOQQs, DRGs, DEMs, Census data, hydrology, land use/land cover, etc.
Historic U.S. Congressional Districts – UCLA Political Science
This site provides digital boundary definitions for every U.S. Congressional District in use between 1789 and 2012. These were produced as part of NSF grant SBE-SES-0241647 between 2009 and 2013.
Housing and Urban Development (U.S.) Open Data – In addition to this open data site, the entire HUD enterprise GIS platform is available for finding data as well as mapping applications and web-based GIS
National Gap Analysis Program – Protected Areas Data Portal (USGS)
The Gap Analysis Program produces data and tools that help meet critical national challenges such as biodiversity conservation, renewable energy development, climate change adaptation, and infrastructure investment. The Protected Areas Database of the United States (PAD-US) is the official inventory of protected open space in the United States. With over 715 million acres in thousands of holdings, the spatial data in PAD-US include public lands held in trust by national, State, and some local governments, and by some nonprofit conservation organizations.
National Historical GIS The National Historical Geographic Information System (NHGIS) provides, free of charge, aggregate census data and GIS-compatible boundary files for the United States between 1790 and 2012.
The National Map (USGS) Provides public access to high-quality, geospatial data and information from multiple partners to help support decision making by resource managers and the public. The National Map is the product of a consortium of Federal, State, and local partners who provide geospatial data to enhance America’s ability to access, integrate, and apply geospatial data at global, national, and local scales.
The National Spatial Data Infrastructure Clearinghouse
(NSDI) – Federal Geographic Data Committee (FGDC)
The National Wetlands Inventory
Digital wetlands data from the U.S. Fish and Wildlife Service, Branch of Habitat Assessment.
National Weather Service GIS data and maps available from the NowCoast Map Viewer.
OpenStreetMap Data – Geofabrik shapefiles
OpenStreetMap is a map of the world, created by people like you, and free to use under an open license.
Starting the Hunt: Guide to Mostly On-Line and Mostly Free U.S. Geospatial and Attribute Data
Guide to finding free sources for U.S. geospatial data (from the University of Arkansas)
EarthExplorer: USGS Geographic Data Download
Quick links to many of the popular USGS raster datasets for direct downloading including Digital Elevation Models (DEMs), National Elevation Dataset (NED), National Land Use & Land Cover (LULC), and the National hydrology Dataset (NHD).
USGS Digital Topographic Map Download
Download free USGS topographic maps at various scales. Use the “Map Locator” to select a site, view the quad boundaries and download a PDF.
Free data: Census TIGER, USGS Landcover & topographic maps, OpenStreetMap, NaturalEarth, etc.
“WeoGeo helps you publish, share, and ultimately derive value, from the location of people and things. We communicate the richness and spatial context of your knowledge beyond what can be shared in a spreadsheet. We’re not just a search engine that will point you to a web page and phone number. We give you data. In a form you can use.”