Paula Dobriansky, US under secretary of state for democracy and global affairs, is to become the US special envoy for Northern Ireland
She will replace Mitchell Reiss starting in the middle of next month.
Ms Dobriansky will take on the role in addition to her current responsibilities.
Mr Reiss, a former director of policy planning at the State Department, has served as special envoy since 2004.
State Department spokesman Sean McCormack said the US remained committed to 'encouraging the full restoration of the Northern Ireland Assembly and devolved government.'