The following National Park System timeline has been extracted from Shaping the System (3rd print edition, 2005) written by Barry Mackintosh, along with other sources.

Natural Areas

Great Sand Dunes National Preserve, created in 2000, encompasses 42,000 acres adjacent to Great Sand Dunes National Park. Virgin Islands Coral Reef National Monument was established in 2001 to protect the coral reef life, sandy beaches, and forests, and to preserve the rich cultural history of the region. Craters of the Moon National Preserve in Idaho was created in 2002 from 410,000 acres that had been added to Craters of the Moon National Monument. The preserve includes lava fields and sagebrush steppe grasslands.

Historical Areas

Lewis and Clark National Historical Park (which incorporated Fort Clatsop National Memorial) was established in 2004 during the bicentennial of Lewis and Clark's expedition. Congress authorized Palo Alto Battlefield National Historic Site, Texas, to recognize the first important Mexican War battle on American soil. Cedar Creek and Belle Grove National Historical Park was established in 2002 to preserve a major Civil War battlefield and plantation in Virginia's Shenandoah Valley. Governors Island National Monument in New York, proclaimed in 2001, preserves the military defenses Castle Williams and Fort Jay, which date from before the War of 1812.

The USS Arizona Memorial at Pearl Harbor, Hawaii, and War in the Pacific National Historical Park on Guam commemorate important military events of World War II, while Manzanar National Historic Site, California, and Minidoka Internment National Monument, Idaho, interpret the wartime internment of Japanese Americans. Rosie the Riveter/World War II Home Front National Historical Park in California commemorates the contributions of those who supported the war effort. The World War II Memorial and the Korean War Veterans Memorial in Washington, D.C., honor those who fought and died in those wars. The Vietnam Veterans Memorial, also in Washington, bears the names of more than 58,000 dead and missing in Vietnam. Minuteman Missile National Historic Site, preserves remnants of a Cold War ICBM installation in South Dakota.

Two sites of terrorist attacks joined the National Park System during this period. The Oklahoma City National Memorial (established in 1997; abolished 2004) commemorates those affected by the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City. Flight 93 National Memorial in Pennsylvania honors the passengers and crew who sacrificed their lives to thwart a planned attack on the Nation's Capital on September 11, 2001. The Presidential sites include a landscaped memorial to Lyndon B. Johnson in Washington, D.C., and residences of Martin Van Buren in Kinderhook, New York; Ulysses S. Grant in St. Louis County, Missouri; James A. Garfield in Mentor, Ohio; Harry S Truman in Independence, Missouri; and Jim.my Carter in Plains, Georgia. Although Congress had authorized the Franklin Delano Roosevelt Memorial in Washington, D.C., in 1959, it was not completed and dedicated until 1997.