Hi, and welcome to RootsChat.
Irish parishes are subdivided into townlands, and there are literally thousands of these across the island. Few of them are named on modern maps, and to add to the difficulty, many of them have similar names; also, when the name is written down, the spelling might vary.
There are three (possibly more) useful sites for identifying and locating townlands:
The IreAtlas Townland Database at
https://thecore.com/seanruad/The Irish Townlands site at
https://www.townlands.ie/The Placenames Database of Ireland at
https://www.logainm.ie/en/All of these tell you which parish a townland is in (important for looking for other records), and the second and third give fuller information on each one, including maps.
Using these sites, the closest name in Co. Tyrone to what you're looking for seems to be Coolmaghery, but you should also consider Coolmaghry and perhaps also Coolageery. I suggest you explore the sites yourself and see what you can come up with.