Use the following instructions to work with the map in Arcgis Pro, due to its size there is a special work flow to follow. (the project package is 68 Gigabytes and it un-compresses to 115 Gigabytes, opening the project as described in the Using ArcGIS Pro 2.1 to make an offline map blog post will download and un-compress the project in the ArcGIS home folder. If your home folder is anything like mine, you won't have enough room for it!
In webbrowser visit https://www.arcgis.com/home/index.html and search for USGS National Map based source type:"Project Package"
Or go directly to the item by clicking on this link: http://www.arcgis.com/home/item.html?id=1e12b7657fa84ec097392b686f6fa05d and download the package.
Note: the the package in 68 Gigabytes in size, broadband is recommended for download.
Once downloaded use 7zip to un-compress the Project to a folder location that is greater than the 116 Gigabyte uncompressed size. You can get 7zip from http://www.7-zip.org/download.html
Use 7-Zip to Extract files...
On a computer with the following specs it took 1 hour to un-compress the project.
Once the project in un-zipped you can use ArcGIS Pro to open the Project.
You will see that this project has the same elements as the example project from the blog, but the map covers the Entire Unites States of America and territories.