Simplify the following text for a Grade 8 native English-speaking person.
Original: To the east of Ireland is Great Britain , separated from it by the Irish Sea . The island is divided between the Republic of Ireland , which covers just under five-sixths of the island , and Northern Ireland , a part of the United Kingdom , which covers the remainder and is located in the northeast of the island .
Simplified: For the country of Ireland that is located on the island , see Republic of Ireland .