I need a basemap to show topography or hillshade of the U.S. but I cannot use the internet so none of the web services or basemaps will work. There has to be some way to get simple topography or contours as an offline file...
The data you're looking for is available from the USGS. I presume you have some sort of internet access (you wouldn't be posting here otherwise) and are looking for data you can use offline. I believe they used to offer their data on disk but it's not clear if they still do for anything but LIDAR point clouds; if you need the data on disk you should contact the USGS directly.
The datasets to look for are:
- 3DEP Elevation - Hillshade
- Elevation Contours
- 3DEP Elevation - Auto Contours
Be warned that these datasets are fairly large (up to the hundred gigabyte range). If you don't need fine detail then "Small scale" datasets are also available and are considerably smaller.