It is usually to the left of the 1 key and above Tab. You can bring up the console by clicking the Tilde (~) key on your keyboard. PC Users Have Another Way We'll need to use console commands. I just never walked over there for some reason. It is behind the yellow crafting house towards the bridge. I thought I had found them all, but in the image below the green dot (aiming recticle) is pointing at the location of a doghouse that I did not know existed where I found Dogmeat. There are 3 or 4 dog houses in sanctuary.
If you are on the PS4 or Xbox One consoles then right now this is your only hope. But, another time he completely disappeared, and I could have sworn I sent him to Sanctuary. Once when I lost Dogmeat, he returned to the gas stations south of Sanctuary.
