The park's lands, heavily mined, logged and quarried in the past, were assembled over the mid-20th century from different purchases by the state, totaling 7,669 acres (31.04 km2; 11.98 sq mi) as of 2014.

Due to its panoramic views of the river and mountains, and easy access by both automobile and rail, it has become a very popular destination for day hikes.

The southernmost section begins just north of Peekskill, abutting the New York National Guard's Camp Smith, following the Bear Mountain Highway (US 6 and 202) around the lower slopes of Anthony's Nose.

[6] Swedish botanist Pehr Kalm sailed up the Hudson in 1749 and wrote one of the earliest accounts of the eastern Highlands: Eastward a high chain of mountains whose sides were covered with woods up to no more than half their height.

The summits, however, were quite barren, for I suppose nothing would grow there on account of the great degree of heat, dryness, and the violence of the wind to which that part was exposed.

[8]As New York began creating its first state parks in the Hudson Valley Region during the 1910s and 20s, it concentrated its efforts on larger tracts it had acquired such as Harriman and Bear Mountain to the southwest and Fahnestock to the east.

Much of the present Hudson Highlands State Park was either part of large estates or owned by commercial interests seeking to exploit their mineral resources.

An organization called the Hudson River Conservation Society (HRCS) worked to preserve the lands by persuading owners to donate them to the state or include clauses in deeds that forbade or greatly restricting quarrying and mining operations on the property.

[9] In 1938 the society made its first significant accomplishment when it persuaded Rosalie Loew Whitney to give the state Conservation Department 177 acres (72 ha) on the northwest face of Breakneck Ridge from the estate of Thomas Nelson, the local landowner from whom Nelsonville took its name.

[9] No more major land acquisitions took place until the 1960s, when the State Council of Parks, forerunner of NYSOPRHP, formed the temporary Hudson River Valley Study Committee to develop a comprehensive plan in response to increasing industrial interest in the area, exemplified by Consolidated Edison's proposal to excavate a large chunk of Storm King Mountain, across from Breakneck, for a hydroelectric plant, which would have involved running power lines across the river and into the eastern Highlands.

[9] The park finally began to come together towards its present form in the next few years, as the Rockefeller family's Jackson Hole Preserve foundation gave New York a deed of trust for land purchases in the Hudson Highlands.

In 1974 William Henry Osborn II, a past HRCS president, donated the 1,033-acre (418 ha) preserve that bears his family name to the state.

[11] It survived appeal, and became a legal precedent establishing New York's right to enforce the state's Endangered Species Act on private property.

Three of New York's five known eastern fence lizard communities are found in Hudson Highlands State Park, near the northern end of its range.

It and the ruins of Bannerman's Castle, listed on the National Register of Historic Places, can only be visited by making advance arrangements through NYSOPRHP for a guided tour.

Some follow, in whole or part, old woods roads left over from the quarrying and mining operations; at other times they climb the steep and rocky peaks directly.