If there is a service you rely upon from the National Atlas of the United States, you may only have until September to take advantage of it. Starting on September 30, 2014, select services from the National Atlas will be merged into the National Map.
The USGS recently released information about the merge, stating:
During this year, National Atlas of the United States and The National Map will transition into a combined single source for geospatial and cartographic information. This transformation is projected to streamline access to maps, data and information from the USGS National Geospatial Program (NGP). This action will prioritize our civilian mapping role and consolidate core investments while maintaining top-quality customer service.
Not all services and GIS data products currently available from the National Atlas will transition to the National Map. The FAQ page about the transition states:
The National Atlas of the United States will be removed from service on September 30, 2014. Some of its products and services will continue to be available from The National Map (nationalmap.gov) while others will not. Everything currently available from the National Atlas will remain accessible until the end of September. We encourage you to explore nationalatlas.gov and to retrieve any products of lasting use to you.
You can access GIS data from the National Atlas Data Download page up until the end of September. In the meantime: “We value the National Atlas customers and stakeholders and want to make this transition as easy as possible,” explained Jay Donnelly, the National Atlas Program Manager. “We will post updates to The National Map and National Atlas Websites as this transition unfolds, including information on the future availability of the products and services currently delivered by nationalatlas.gov.” You can follow those updates on the National Atlas transition page. One of the declared casualties of the merge is the National Atlas Map Maker which will be shutdown in September: The National Map Viewer at nationalmap.gov will be your source for data visualization after that date. Thematic map layers currently viewable in the Map Maker will not be ported to The National Map Viewer.