1. Online GIS Data Sources

EROS Data Center - Great source for U.S. topographic data and internatonal DEMs

David Rumsey Historical Map Collection - Digital, georeferenced historical maps

GIS Data Depot

Geography Network

Geospatial One Stop

Global Spatial Data Infrastructure Association (GSDI) - List of portals by scale

FGDC Clearinghouse Registry - Registry of data portals

Harvard Geospatial Library - Free Digital Chart of the World (DCW) data and historic maps

Starting the Hunt: Guide to Free Geospatial Data - Great site for state-wide data

US National Atlas

MapAbility.com - Free VMAP1 international data

Boston Atlas

Boston Redevelopment Authority

Brookline GIS

Cambridge GIS

MassGIS - State GIS Office - Great site for Massachusetts

Mass Dept. of Fish & Game

Mass Dept. of Public Health

Starting the Hunt: Guide to Free Geospatial Data - Great site for state-wide data.

Connecticut Map and Geographic Information Center (MAGIC)

Connecticut Department of Environmental Protection GIS Data

Maine Office of GIS

New Hampshire GRANIT

New York State GIS Clearinghouse

Pennsylvania Spatial Data Access (PASDA)

Rhode Island GIS

Vermont Center for Geographic Information, Inc. (VCGI)

Bureau of Transportation Statistics Atlas Data

CIA World Factbook - International maps and statistics

Federal Emergency Management Agency (FEMA)

Famine Early Warning System - Livelihood analysis and mapping.

GEONet Names Server (GNS) - Get coordinates from NGA's international place name server

NASA Land Processed Distributed Active Archive Center

National Center for Health Statistics

National Historic GIS - Historic census geography provided by U of Minnesota

National Geodetic Survey

National Geospatial Intelligence Agency (NGA)

NGA Raster Roam Engine - Good for international data

National Institute of Justice Mapping & Analysis for Public Safety

National Oceanic and Atmospheric Administration (NOAA)

NOAA National Environmental, Satellite, Data, and Information Service

NRCS Soil Survey

US Census Bureau

US Environmental Protection Agency (EPA)

US Fish & Wildlife

USDA Geospatial Gateway

USGS EROS Data Center - Great source for U.S. topographic data.

USGS GEO-Data Explorer (GEODE)

USGS Node of the National Geospatial Data Clearinghouse

USGS Water Resources NSDI Node

World Heritage Centre - Index of National Mapping Agencies

Index of International Statistical Agencies

Afghanistan Information Management Service

Africa Data Dissemination Service

Australian Consortium for the Asian Spatial Information and Analysis Network (ACASIAN)

Center for International Earth Science Information Network (CIESIN)

EastView Cartographic - Commercial vendor, great source of international topo maps and data

Famine Early Warning System (FEWS Net) - Livelihood maps and GIS data

FAO Geoportal

GEOBIS - Commercial vendor specializing in international GIS and statistical data

Geographic Information Support Team (GIST) - Great source of international admistrative geography

Gfk GeoMarketing - Commercial vendor, great source of international administrative geography

Go-Geo UK GIS

HumanitarianInfo.org - Index of Humanitarian Information Centers

MesoStor - Mesoamerica's free data delivery system

NatureServe - World-wide animal data for download

Poverty Mapping - a global spatial database of poverty mapping examples and possible indicators

United Nations Environment Programme (UNEP_ - Global & Regional Integrated Data Centres

UNEP GEO Data Portal

United Nations Statistics Division

World Wildlife Foundation (WWF) Data Download - International ecological and hydrological data

University of Maryland Global Landcover Facility - Open source for Landsat TM and ETM data

Landsat

SPOT Image

GeoEye

Digital Globe

MDA Federal, Inc.