Leaving my tenure-track position for industry in January 2021, Things have really gone downhill in our department because of Covid-19, and I and a few other colleagues (also on the tenure track) are planning to leave at the end of this semester, for industry.
To whom should I first resign with?  The Chair of the department?
My mind is made up, so I'm seeking the least painful path forward.  I have a job offer lined up already.
Thanks in advance.
When I left I first informally talked to my direct line manager to whom I usually reported (which was in my case the head of the department). Then my official (and signed) letter went to human resources to formalize the termination of my contract. Then talk to your PhD students / postdocs etc .. It was a slightly different situation as I left after I already had tenure but I guess the same procedure might work best for you as well.