There are several efforts to preserve and archive data and public web content, but the Internet Archive is a perennial favorite. Their End of Term initiative has been archiving governmental sites during presidential transitions all the way back to Obama.
It’s a way to see what agency websites looked like during the Obama, Biden, Trump or even Bush years. Each term archive is saved into a collection, making it searchable for various agencies or terms.
It doesn’t include most local government sites – just federal. But that’s still a tremendous effort and a good thing to have around. Keep it in mind, reporters!