Archeological evidence found in the state from this time includes a range of pottery types and styles, burial mounds, pipes, bows and arrows, and ornaments.

They were a matriarchal society that lived in stockaded villages of large longhouses, but their numbers were greatly reduced by disease and warfare with the Five Nations of the Iroquois, and by 1675 they had died out, moved away, or been assimilated into other tribes.

[7][8] After the demise of the Susquehannocks, the lands of the Susquehanna River valley were under the nominal control of the Iroquois, who also lived in longhouses, primarily in what is now the state of New York.

[7][9] To fill the void left by the demise of the Susquehannocks, the Iroquois encouraged displaced tribes from the east to settle in the Susquehanna watershed, including the Shawnee and Lenape (or Delaware).

[7][8] The French and Indian War (1754–1763) and subsequent colonial expansion encouraged the migration of many Native Americans westward to the Ohio River basin.

[7] On November 5, 1768, the British acquired land, known in Pennsylvania as the New Purchase, from the Iroquois in the Treaty of Fort Stanwix; this included what is now Ricketts Glen State Park.

[11] About 1890 a Native American pot, decorated in the style of "the peoples of the Susquehanna region", was found under a rock ledge on Kitchen Creek by Murray Reynolds, for whom a waterfall is named.

[19][23][24] While on a hunting trip on Loyalsock Creek north of the park in 1850, brothers Elijah and Clemuel Ricketts were frustrated at having to spend the night on a hotel's parlor floor.

[16][19] Elijah's son Robert Bruce Ricketts, for whom the park is named, joined the Union Army as a private at the outbreak of the American Civil War and rose through the ranks to become a colonel in the artillery.

In 1876 and 1877, Ricketts ran the first summer school in the United States at his house and hotel; one of the teachers was Joseph Rothrock, later known as the "Father of Forestry" in Pennsylvania.

[16][31] One of the highest spots on North Mountain (and in the park today) was an outlook point where Ricketts built a 40-foot (12 m) wooden observation tower for his guests.

In 1872 he sold 14,000 acres (5,700 ha) north of the park to a group of investors that included himself; this deal seems to have been for shares of stock (not cash), and the deed for the sale was not recorded until 1893.

Rail lines were built to the mills at Ricketts, including the Bowman Creek branch of the Lehigh Valley Railroad which opened in 1883, and also provided passenger service to the hotel on Lake Ganoga.

A second dam and lake were added in 1909 and the icehouses were on state park land; the ice industry supported the small village and post office of Mountain Springs.

[3][13][48] The state's original plans for the new park included building an inn, an 18-hole golf course and country club, and a winter sports complex for skiing, ice boating, and tobogganing, as well as a beach with bathing facilities, cabins, and a tent camping area.

Out of concern for greater safety, footbridges with handrails replaced those made from hewn logs, overhanging rock ledges were removed in places, and the trail was rerouted near some falls.

On April 20, 1958, the 1907 concrete dam at Lake Leigh developed a hole, causing Pennsylvania State Police to evacuate close to 2,000 people from the park.

Part of the 648th Aircraft Control and Warning Squadron based at Fort Indiantown Gap, the radar station was a "frontline defender of national security".

[63] That same year training was undertaken by local fire companies to rescue people injured in the park when icy conditions make reaching and transporting them especially treacherous.

[75] The DCNR has named Ricketts Glen one of "25 Must-See Pennsylvania State Parks", citing its old-growth forest and many waterfalls and its status as a National Natural Landmark.

Within the park, Kitchen Creek has its headwaters on the dissected plateau, then drops approximately 1,000 feet (300 m) down the Allegheny Front in 2.25 miles (3.62 km).

[29][55][76] The rocks exposed in the park were formed in the Devonian and Carboniferous periods between 370 and 340 million years ago, when the land was part of the coastline of a shallow sea that covered a great portion of what is now North America.

Tremendous pressure caused the formation of the sedimentary rocks that are found in the park and in the Kitchen Creek drainage basin: sandstone, shale, siltstone, and conglomerates.

[55][78][82] The effects of glaciation have made Kitchen Creek within the park "unique compared to all other nearby streams that flow down the Allegheny Front", as it is the only one with an "almost continuous series of waterfalls".

The DCNR recognizes three named waterfalls in Ricketts Glen just south of Waters Meet, plus Adams Falls 2 miles (3.2 km) farther downstream at PA 118.

Several factors contribute to the high total of bird species observed: there is a large area of forest in the park, as well as great habitat diversity.

Canada goose are present in the park and have been classified as a "pest" due to their high numbers and the large amount of fecal waste they leave on the shores of Lake Jean.

Common game animals include black bear, gray squirrel, ring-necked pheasant, ruffed grouse, wild turkey, and white-tailed deer.

The walks give school groups, scouting organizations, and other visitors a close and informed look at natural wetlands, old-growth forests, waterfalls, flora and fauna, and geologic formations.

[111] In summer and fall, park educators lead "Ghost Town Walks" to the ruins of the lumber village of Ricketts and to adjoining State Game Lands.