Beyond Iowa GIS Data

Census:

Census Data

2010 TIGER/Line Shapefiles

Census Boundary & Annexation shps

World Wide Open Data Sites

Census Tiger w/availability info

US Census FactFinder tabular data (use Advanced Search)

American Community Survey or dataferrett

US Census Tiger Products

US Census Gazetteer

Maps and Data (main page)

Geocoder

TIGER/Line Shapefiles


USGS:

State Geologic Data

The National Map - Data Delivery

USGS websites

USGS National Map Viewer

National Atlas

USGS Data Download and Visual

Earth Explorer

Earthquakes

(expand the list in the upper left to access the Download button. It will provide you with multiple download options CSV, GeoJson, KML, and more.

Also, click the gear (Settings) in the upper right to change what earthquakes are visible on the map)


NOAA:

GIS Portal

Iowa Tornadoes 2016 (kml)

KML download page

NOAA Rest Services

NOAA Shapefiles

Electronic Naviagtion Charts


Other US Govt:

NRCS

National Park Service

Army Corps of Engineers Public GIS Data

USDA Geospatial Gateway

National Park Service

NWS Damage Assessment Tool (view & download)

EPA Geospatial Data Download

Ntl Map Small Scale Data Download

FAA

USDA Web Soil Survey

Data.gov

NASA Earth Observations



Other:

Developing Countries data

mapcruzin

Libre Map Project

OpenStreetMap Data

Downloading Openstreetmap data

GEBCO

GeoData

Hurricane Data

Geocommunity Data Depot

National Wetlands Inventory

Potential Datasources via openstreetmap

weogeo (article)

NHGIS

Historic GIS Clearinghouse

Appalachian Trail

Data.gov

NGIA

NDEP

Zillow Neighborhoods

Zillow Data

SHELDUS

Red Cross

Natural Earth

USNG Information Center

GitHub

rtwilson

Open Data Inception

CIESIN

Atlas of the Biosphere

World Resource Institute

The FAO Geonetwork

Opentopography

GIS Data Repositories (Dr. Karen Payne UGA)

Robin Wilson

Stanford

Terra Populus

DIVA-GIS Data

UNEP Data Explorer

US Building Footprints