First State National Historical Park Act

First State National Historical Park Act - Establishes the First State National Historical Park in Delaware, to be administered as a unit of the National Park System.

Specifies that the purpose of the Park is the preservation, protection, and interpretation of the nationally significant cultural and historic resources associated with early Dutch, Swedish, and English settlement of the colony of Delaware and parts of the colony of Pennsylvania and Delaware's role in the birth of the United States and as the first state to ratify the Constitution.

Bars the establishment of the Park until it is determined that sufficient land or interests have been acquired from among specified historic sites within the boundary of the Park to constitute a manageable park unit. Instructs the Secretary to publish a notice in the Federal Register of the Park's establishment, including an official boundary map.

Allows the the Secretary to acquire: (1) by purchase from a willing seller, donation, or exchange, all or a part of any of such sites, including easements or other interests; and (2) by donation only, all or a part of the property identified as "Proposed NPS (National Park Service) Site," including easements or other interests, and the property identified as "Area for Potential Addition by Donation." Adjusts the boundary of the Park to reflect the acquisition of lands or interests in such sites.

Authorizes the Secretary to: (1) provide interpretive tours to sites and resources in Delaware and Pennsylvania located outside the Park's boundary and associated with the purposes for which the Park is established under this Act; and (2) enter into cooperative agreements with Delaware and Pennsylvania and other specified entities to mark, interpret, and restore nationally significant historic or cultural resources within the Park, if those agreements provide for reasonable public access to such resources.

Limits the federal share of the total cost of any activity carried out under such an agreement to 50% of that cost. Permits the non-federal share to be in the form of in-kind contributions or goods or services fairly valued.

Requires the completion of a management plan for the Park.

Requires completion of a study assessing the historical significance of additional properties in Delaware and Pennsylvania associated with the Park. Requires such study to include an assessment of the potential for designating such properties as National Historic Landmarks.

Authorizes appropriations.

Amends the Omnibus Public Land Management Act of 2009 to state that the amount authorized to be appropriated to carry out the Preserve America program not appropriated as of this Act's enactment date shall be reduced by $6.5 million.