Law and legislation 550 National parks and reserves 112 Historic sites 80 Boundaries 65 Water resources development 44 Land titles 35 Registration and transfer 35 more ... Cultural property 29 Protection 29 Finance 26 Wild and scenic rivers 25 Hydroelectric power plants 24 Research 23 Trails 23 Wilderness areas 22 Water reuse 18 Forest reserves 17 Real property, Exchange of 17 Appropriations and expenditures 15 Monuments 15 Watershed management 15 Memorials 14 Recreation areas 14 Energy conservation 13 Groundwater 11 Biens réels 10 Energy development 10 Dams 9 Historic preservation 9 History 9 less ...