Lewis and Clark National Historical Park Designation Act

Title I: Lewis and Clark National Historical Park Designation Act - Lewis and Clark National Historical Park Designation Act - (Sec. 103) Designates the Lewis and Clark National Historical Park as a unit of the National Park System.

Defines the boundaries of the park, located in the States of Oregon and Washington, according to a map entitled "Lewis and Clark National Historical Park, Boundary Map" (December 2003), which includes the Fort Clatsop National Memorial and other specified lands.

Authorizes the Secretary of the Interior to acquire land, interests in land, and improvements therein within park boundaries. Directs that such land may be acquired only with the consent of the owner except with regard to specified corporately owned timberlands. Requires the Secretary, if the owner of specified corporately owned timberlands agrees to sell as a result of actual condemnation proceedings or in lieu of condemnation proceedings, to enter into a memorandum of understanding with the owner addressing post-acquisition management of those lands.

Directs the Secretary to transfer, subject to valid rights (including withdrawals), to the Director of the National Park Service management of any Federal land at Cape Disappointment, Washington, that is within the boundary of the park. Revokes all withdrawals of a specified 20-acre parcel depicted as a "Memorial to Thomas Jefferson" and directs the Secretary to establish a memorial to Thomas Jefferson on the parcel. Authorizes the Secretary to enter into an agreement with the State of Washington providing for the administration by such State of the land within the boundary of the park known as Cape Disappointment State Park.

(Sec. 104) Requires the Secretary to: (1) administer the park in accordance with this title and with laws generally applicable to the NPS; and (2) prepare an amendment to the general management plan for Fort Clatsop National Memorial to guide management of the Park. Authorizes the Secretary to enter into cooperative management agreements with appropriate officials in Oregon and Washington with respect to the conduct of living exhibits and interpretive demonstrations.

(Sec. 105) Repeals specified law regarding the establishment and administration of Fort Clatsop National Memorial.

(Sec. 106) Prohibits anything in this title from being construed to: (1) require any private property owner to permit public access (including government access) to such private property; or (2) modify any provision of law concerning public access to or use of private lands.

States that designation of the Park shall not be considered to create any liability, or to have any effect on any liability under any other law, of any private property owner with respect to any persons injured on such private property.

Prohibits anything in this title from being construed to modify any authority to regulate the use of private land within the Park's boundaries.

(Sec. 107) Authorizes appropriations.

Title II: Lewis and Clark Eastern Legacy Study - (Sec. 201) Directs the Secretary to update the 1958 Lewis and Clark National Historic Landmark theme study of the eastern sites of the Corps of Discovery expedition used by Lewis and Clark in the preparation phase starting at Monticello, Virginia, and traveling to Wood River, Illinois, and the return phase from Saint Louis, Missouri, to Washington, District of Columbia, including sites in Virginia, Washington, District of Columbia, Maryland, Delaware, Pennsylvania, West Virginia, Ohio, Kentucky, Indiana, and Illinois. Requires the study's focus to be on developing historic context information to assist in the evaluation and identification of sites eligible for listing in the National Register of Historic Places or designation as a National Historic Landmark. Requires the Secretary to report to Congress on any findings, conclusions, and recommendations.

(Sec. 202) Authorizes appropriations.