The OPW's responsibilities relate to two main areas: Estate Management, including Heritage Services, and Flood Risk Management. The OPW provides accommodation for Government Services and manages much of the State’s property portfolio. The OPW has responsibility for caring for 780 heritage sites, including national monuments, historical parks, gardens and buildings. It is the Government’s principal engineering agency, providing an engineering service to the Flood Risk Management and Estate Management functions of the OPW as well as to other Government Departments.