No, you cannot visit Northern Ireland with an Ireland Visit Visa. A visit visa for Ireland does not allow travel to Northern Ireland, which is part of the UK. A separate UK visa is needed to visit Northern Ireland, unless you are from a country that doesn't require a visa for the UK. Even though the Republic of Ireland and Northern Ireland share a border, they each have their own immigration regulations. If you cross into Northern Ireland without the needed visa, UK immigration may refuse entry or impose penalties.