Original sentence: It is composed of the Republic of Ireland which covers five sixths of the island (south, east, west and north-west) and Northern Ireland, currently a part of the United Kingdom, which covers the northeastern sixth of the island
Edited sentence: It is composed of the Republic of Ireland which covers five sixths of the island (south, east, west and north-west) and the Six Counties of Northern Ireland, currently a part of the United Kingdom, which covers the northeastern sixth of the island