The surface, subsurface and above the surface of the earth is covered and filled by billions of natural and constructed features, boundaries and phenomena. The information about the location as well as other attributes of these features are crucial to the public and all levels of business, government and academia. Over eighty percent all data refer to them. The term spatial, geographic, or geospatial data is used interchangeably for the kind of data that has both locational information as well as other attributes. For example, a house has an address -which is locational information- and has other attributes such as price, number of rooms, owner, type, etc., which are attribute information.
There are different kinds of features, boundaries and phenomena. Rocks, minerals, oil, gas, air,oceans, lakes, and rivers are examples of natural features. Buildings, roads, railroads, on the other hand, are examples of constructed features. Boundaries separate features such as state, city, county, and district boundaries. Earthquakes, faults, volcanism, tornado, tsunami, flood, fire and landslide are example of phenomena.

The U.S. Board on Geographic Names has a geospatial database with over two million natural and cultural features in the United States. The database is in the public domain, which can be displayed and downloaded.
The links on the right give access to picabytes of geospatial data, geospatial metadata and helps of all kinds. No matter at which level you work with geospatial data, these sites must be rememberd and their uses mastered.