In Genesis, God closed the door of Noah’s Ark after Noah entered.
Genesis 7:16 says that Noah, his family, and the animals entered the ark as commanded, and then “the LORD shut him in.” The statement emphasizes divine protection and marks the point at which the occupants were enclosed before the floodwaters rose.
The text does not say that Noah personally bolted the door, nor does it identify an angel as the one who closed it. Artistic versions may show Noah handling the entrance, but that is not the specific action described in Genesis. The verse also says that the animals entered in pairs, although Genesis gives additional instructions about clean animals earlier in the account.
This detail belongs to the biblical narrative rather than to a confirmed historical record of a surviving vessel. It is nevertheless one of the clearest action statements in the ark story, making “God” the precise answer to the question of who shut the door.