Blackstone River Valley National Heritage Corridor Amendments Act of 1994 - Modifies the boundaries of the Blackstone River Valley National Heritage Corridor.

Requires the Blackstone River Valley National Heritage Corridor Commission to revise the Cultural Heritage and Land Management Plan to address the boundary change and include a natural resource inventory of areas or features that should be protected, restored, managed, or acquired because of their contribution to the understanding of national cultural landscape values. Prohibits changes other than minor revisions in the approved plan as amended without the approval of the Secretary of the Interior.

Extends the date of termination of the Commission until ten years after this Act's enactment, subject to specified conditions. Directs the Secretary to approve an additional extension if the Secretary finds that: (1) the Governors of Massachusetts and Rhode Island provide adequate assurances of continued tangible contribution and effective policy support toward achieving the purposes of the Corridor; and (2) the Commission is effectively assisting Federal, State, and local authorities to retain, enhance, and interpret the distinctive character and nationally significant resources of the Corridor.

Authorizes the Secretary to undertake a limited program of financial assistance for the purpose of providing funds for the preservation and restoration of structures on or eligible for inclusion on the National Register of Historic Places within the Corridor which exhibit national significance or provide a wide spectrum of historic, recreational, or environmental education opportunities to the general public.

Specifies that nothing in the Act establishing the Corridor shall be construed to affect or authorize the Commission to interfere with: (1) the rights of any person with respect to private property; or (2) any local zoning ordinance or land use plan of the Commonwealth of Massachusetts or a political subdivision of such Commonwealth.

Increases and extends the authorization of appropriations under the Act.

Blackstone River Valley National Heritage Corridor Amendments Act of 1993 - Modifies the boundaries of the Blackstone River Valley National Heritage Corridor pursuant to a specified Act (the Act).

Requires the Blackstone River Valley National Heritage Corridor Commission to revise the Cultural Heritage and Land Management Plan to address the boundary change and include a natural resource inventory of areas or features that should be protected, restored, managed, or acquired because of their contribution to the understanding of national cultural landscape values. Prohibits changes other than minor revisions in the approved plan as amended without the approval of the Secretary of the Interior.

Extends the date of termination of the Commission until ten (currently, five) years after the Act's enactment, subject to specified conditions. Directs the Secretary to approve an extension if the Secretary finds that: (1) the Governors of Massachusetts and Rhode Island provide adequate assurances of continued tangible contribution and effective policy support toward achieving the purposes of the Act; and (2) the Commission is effectively assisting Federal, State, and local authorities to retain, enhance, and interpret the distinctive character and nationally significant resources of the Corridor.

Authorizes the Secretary to provide funds for projects in the Corridor that exhibit national significance or provide a wide spectrum of historic, recreational, environmental, educational, or interpretive opportunities, without regard to whether the projects are in public or private ownership, subject to specified requirements.

Increases and extends the authorization of appropriations.