Blackstone River Valley National Heritage Corridor Act of 1986 - Establishes the Blackstone River Valley National Heritage Corridor in Rhode Island and Massachusetts, cradle of the American industrial revolution. Establishes the Blackstone River Valley National Heritage Corridor Commission to hold hearings and acquire real property within the designated Corridor by gift or purchase with private money from a willing seller. Directs the Commission to develop a Cultural Heritage Plan for the Corridor which sets its boundaries, inventories the historically significant property to be maintained, establishes standards, and develops an historic interpretation plan. Requires the Commission to implement the Plan, granting priority to preserving the Blackstone Canal, providing information for visitors, and encouraging private and intergovernmental cooperation in building restoration and appropriate land use. Terminates the Commission in five years with an up to three-year extension. Requires the Secretary of the Interior to help prepare the Plan and appropriate visitor information and displays, providing technical assistance to the Commission if requested. Requires the cooperation of other Federal agencies. Authorizes appropriations.