When I played a while back I found some giant walking around. It was around a place where it had a note about"going into the sewers" it was I'm the northwest I think. I want to go back there cause I'm much stronger but can't find it.

They are called Behemoth.

There are a number of points for them around the map where they respawn.

From your description that one could be near Walden Pond.

IIRC look for an arranged pile of cars.

or Google Behemoth locations fallout 4.

Possibly near the Corvega Assembly Plant and the Super Duper Mart. There's a respawning Behemoth there. There's another respawning Behemoth up by Recon Bunker Theta, but that doesn't sound like the right location.

It's the one near the Walden Pond. Look near the entrance to the severs.

Really? What are they doing outside of skyrim

But on a serious note, yeah, they are actually a type of super mutant called behemoths. You'll encounter them at really very high levels. Although I know one can be encountered very early on if you're doing the brotherhood main quest line. Personally, haven't encountered any other than that.

Maybe you mean Swan? A particularly nasty behemoth living in Swan's Pond? He has pieces of the Swan boats attached to him as armor.

Yes there's one South of Waldon Pond hanging around near a red car, massive, threw a rock and half killed me, there's high motorway a bit to the West, I've been looking for a way up.... I could manage from up there, otherwise Sprint for your life !