An engineering marvel originally built in 1884, the Georgetown Loop railroad fulfilled the hopes of Georgetown citizens to become a prosperous settlement connected to Denver and points east. In connecting Silver Plume and Georgetown, towns over 2 miles apart, the tracks scaled an elevation of 640 feet over mountainous terrain, requiring trestles, cuts, fills, loops, and curves totaling 4.5 miles. Today the Loop is once again a popular tourist attraction and an uncommon way to see the Clear Creek Valley. Along the route visitors may stop for guided tours of a historic silver mine. The park is located on 978 acres and includes an 1884 depot, the Morrison Interpretive Center, two 1860s mines, an 1871 mill building, four reconstructed mine buildings, a locomotive maintenance building, the 1874 Pohle House, and a new rolling stock shelter.

A second, individual website for the park can be found here.

The park offers a short film, train rides, tours, and exhibits.

The Museum, through artifacts, photographs, and paintings tells the story of Oklahoma's territorial period. The facility covers approximately 10,000 square feet divided between two floors. The first floor presents exhibits embracing the first land run in the territories and the events leading up to the day, April 22, 1889. Exhibitions also cover the territorial lifestyle, including the homesteader and the urban aspect. Items related to territorial government, transportation, education, entertainment, and the statehood experience are presented in the second floor exhibits. Attached to the museum is the Historic Carnegie Library of Guthrie. Built in 1902, it hosted many important political and social events in early Oklahoma history and still houses its original furnishings.

The museum offers exhibits, tours, and educational and recreational events and programs.

In 1854, John Anderson Penn settled in the rugged cedar-covered hills of southwest Dallas County—an area known as the Cedar Mountains. Today, remnants of the original Penn Farm survive intact in the confines of Cedar Hill State Park. Penn Farm Agricultural History Center pays tribute to the disappearing Texas family farm and affords a glimpse into agrarian history as farm machinery took the place of the horse and mule almost a century ago. It includes reconstructed and historic buildings from the mid-1800s through the mid-1900s.

The site offers tours and occasional recreational and educational events.

The Harry S Truman National Historic Site preserves the 1885 Queen Anne residence in which Harry S Truman lived between the ages of 22 and 88 (beginning in 1919); the Truman Farm Home in Grandview, Missouri, where Truman lived between 1906 and 1917; and several family homes. Collections consist of more than 53,000 artifacts. Truman (1884-1972) served as the 33rd President of the United States between 1945 and 1953. During this time he desegregated the military, approved nuclear weapon use on Japan, adopted the Marshall Plan, and witnessed the founding of the United Nations.

The site offers a 12-minute introductory slide presentation, tours of the Queen Anne residence, school tours of the Queen Anne residence, cell phone tours of the farm and Queen Anne sites, and Junior Ranger activities. Reservations are required for all school visits. The website offers four lesson plans, photo tours, an artifact of the month feature, and a list of the more than 1,100 books owned by Truman.

Lyndhurst was one of the most famous examples of Gothic Revival architecture in 19th-century America and served as the New York home to former New York City mayor William Paulding, merchant George Merritt, and railroad tycoon Jay Gould, respectively. The site serves as a great example of money and power in the Gilded Age.

Lyndhurst offers 30-minute group tours and award-winning education programs (on-site or in-schools) designed to follow New York State standards of learning.

The Frederick Law Olmsted National Historic Site commemorates the life of Frederick Law Olmsted (1822-1903), owner of the world's first full-scale landscape design office.

The site offers guided walking tours of Boston-area parks designed by Olmsted, outreach slide presentations, custom-designed educational programs in the "Emerald Necklace" parks, an educator's packet, and teachers' workshops.

The Frederick Law Olmsted National Historic Site is closed for construction. The site is expected to reopen in 2010.

The Ferguson Mansion was built in 1907. T.B. Ferguson was appointed to serve as Oklahoma's sixth territorial governor by President Theodore Roosevelt and governed from November 1901 until January 1906, longer than any other territorial governor. In 1927, the famous novelist Edna Ferber stayed in the Ferguson home where she found much of the material for her novel, Cimarron.

The home offers tours.

The Society operates two historic house museums: 1883 Maple Grove and the 1882 Propst House.

The society offers lectures, research library access, and occasional educational and recreational events; the museums offer tours.

In 1778, General George Washington ordered Fort Mifflin, built in 1777, to hold off the British Navy while the Continental Army traveled to its encampment site at Valley Forge. While the Continental soldiers were eventually forced to abandon the fort, Washington and his troops were able to reach their destination thanks to the soldiers' efforts. Since, the fort has served as a War of 1812 garrison, Civil War prison, and a munitions depot for both World Wars. Today, the fort contains 14 restored structures, the originals of which were built between 1778 and 1815.

The fort offers tours; weapons demonstrations; cannon firings; overnight Scout programs; and educational programs on the U.S. flag, the Revolutionary War, and the Civil War.