Presidential Sites Improvement Act - Directs the Secretary of the Interior to award grants to owners or operators of Presidential sites for major maintenance and improvement projects. Defines "Presidential site" as a site related to a President of the United States that has national significance, is open to the public, and is owned or operated by a State or private institution, organization, or person.
Establishes the Presidential Site Grant Commission to review applications for grants and to make recommendations for the awarding of grants under this Act.