The new Northern Ireland Secretary has promised to help build stability and peace in the region.
Theresa Villiers, MP for Chipping Barnet, takes over from Owen Paterson following a Cabinet reshuffle by Prime Minister David Cameron.
Mr Paterson has moved to the Department for the Environment, Food and Rural Affairs.
Ms Villiers takes up the post as the Northern Ireland Office considers reforms to powersharing structures at Stormont and comes under pressure to deal with growing tensions over parading in Northern Ireland.
She said: "Huge progress has been made in Northern Ireland over recent years. As the headlines in the past few days demonstrate, however, we still have some way to go if we are to overcome the divisions in society and build a genuinely shared future."
She said the Government would stand by agreements made over the past two decades and political institutions established. She added she was acutely aware of the need to rebalance the economy and the Government would put pressure on those who resort to terrorism and violence to pursue their objectives.
"So I look forward to working with the Executive, political parties and people from right across the community to build a stable, peaceful and prosperous Northern Ireland for everyone. This is a great opportunity which I relish," she added.
Ms Villiers, 44, was an MEP before becoming a Conservative MP. She attended Oxford and is a former barrister. She has taken an interest in aviation policy, objecting to the expansion of airports in the south-east of England and supporting high speed rail links.
During his time as Northern Ireland Secretary, Mr Paterson's most high-profile project was his effort to secure devolution of corporation tax powers to Northern Ireland, believing that would help rebalance an economy heavily reliant on the public sector, but that potential change has yet to be finalised.
He was accused by unionists and republicans of interfering in Stormont politics when he criticised their failure to agree a strategy on combating sectarianism. Mr Paterson was credited over the Government's widely welcomed handling of the Saville Inquiry findings into the death of 14 civil rights protesters in Londonderry on Bloody Sunday in January 1972 when paratroopers opened fire.