Jeleliu is probably Peleliu, Ulithi is correct, Holiday Hill is a mystery to me, and New Challdinia is New Caledonia, Leyte is correct.
Is that written on the sheath as if in sequential order? If so, that was a odd tour through a few of the nastier places (Peleliu, Leyte) in the Pacific War. New Caledonia became a staging area early in the war (as was Hawaii of course) and Ulithi became a major Navy repair facility late in the war.
https://en.wikipedia.org/wiki/Battle_of_Peleliu
https://en.wikipedia.org/wiki/Ulithi#Second_World_War
https://en.wikipedia.org/wiki/Battle_of_Leyte
The Catt 225Q is a good knife and quite usable today (assuming condition is OK). If you do use it, I recommend getting a modern replica sheath the old one has earned its rest, especially with the markings.
Edit/addition: Holiday Hillih (?) might be Halmahera, but I don't think it saw action in WW2:
https://en.wikipedia.org/wiki/Halmahera