To amend the Internal Revenue Code of 1986 to allow individuals to designate any portion of their income tax overpayments, and to make other contributions, for the benefit of units of the National Park System.

Amends the Internal Revenue Code to allow an individual to designate a specified portion (but not less than $1) of any income tax overpayment and any cash contributions to be used for the benefit of units of the National Park System. Establishes a National Parks Trust Fund into which appropriated or credited amounts are received. Authorizes the Secretary of the Treasury to pay, not less often than quarterly, specified expenditures from the Trust Fund to the Director of the National Park Service. Requires that expenditures from such Fund be used only for operations, maintenance, and construction within the units of the National Park System. Prohibits the use of such expenditures for the purposes of land acquisition.