There’s like a dozen places with that name in Taiwan… I guess people loved naming places that back in the days.
Some places are so named because the entire region is shaped like a turtle, and there’s no other way to name the place shaped like the turtle’s head.
Other places such as this one… is name because… well…
There are enough places named 龜頭 that looks nothing like anything that makes me wonder if it’s a common Austronesian location name.
Maybe 頭 is Tau, Austronesian for people, and Ku is some kind of prefix.