There is a concerted effort to try to back up US government websites by ArchiveTeam before they can be deleted: https://wiki.archiveteam.org/index.php/US_Government

All you need is an unmetered internet connection and something that will run their virtual machine which is here: https://wiki.archiveteam.org/index.php/ArchiveTeam_Warrior. Once you've downloaded and booted version 4.1 of the virtual machine, select "U.S. Government" as the project and you're good