Hold down the fort or hold the fort is an idiom typically used to mean managing or maintaining control of a situation, place, or responsibility while someone is temporarily absent. The idiom originates from military language, where soldiers held a fort or defensive position when others were absent.

To "hold down the fort" is something you would say to someone when you temporarily ask them to take control or command of a situation, business, or place in your absence. Essentially, you're asking another person to look after things while you're away from the site.