Sachem's Wood estate (1784–1910)

The Science Hill site is not known to be inhabited until 1784, when it was purchased by James Hillhouse, New Haven's largest landowner.^[7] Hillhouse built a wide road, now Hillhouse Avenue, to extend to the foot of the hill, but planned to use the ridge itself for his own residence, and called the tract "Temple Square."^[7] Hillhouse bequeathed the land to his son, James Abraham Hillhouse, who built a family estate known as Sachem's Wood, a name derived from European-descended Hillhouse's supposedly Native American facial features.^[8] A secluded mansion, designed by Ithiel Town, was finished in 1828 at the present-day site of Kline Biology Tower.^[7] Later, the surrounding lots were developed into revivalist mansions, but the large Hillhouse tract remained an undivided estate.

Science education at Yale College came in 1802 with the appointment of Benjamin Silliman as professor of chemistry. Although Silliman was given a basement laboratory on Old Brick Row, sciences were marginal within the university's curriculum.^[9] In 1847, the Sheffield Scientific School was founded as a separate school of Yale, and it began expanding its campus between the university's main campus and Sachem's Wood. Although a corporate entity of the university, the school was socially and administratively separate from the rest of Yale. Yale College students did not attend Sheffield classes, and Sheffield students lived in societies and dormitories separate from Yale College students.^[10] Over time, the division caused Yale's science education and research efforts to suffer.^[11]

Purchase by Yale and early growth (1910–1945)

By the turn of the 20th century, there were few large, undeveloped tracts of land near Yale's campus. The largest was Sachem's Wood, which a group of Yale alumni purchased from the Hillhouse family in 1905, hoping to give Yale room to expand.^[12]: 331 Seeking to build new science facilities and bring the Sheffield Scientific School under greater university control and strengthen university science research, Yale raised funds from Olivia Sage to purchase the estate in 1910, renaming it Pierson-Sage Square.^[7][12][13] It was the largest single acquisition of land since Yale's founding, and the university drew up two early site plans for the property: a Frederick Law Olmsted site plan in 1905, and a university-wide master plan by John Russell Pope in 1919. Neither was fully enacted, but elements of both are evident throughout the present-day site.^{[14][15]: 144}

Shortly after the land acquisition, a gift was received from brothers Henry and William Sloane for a new physics laboratory.^[12]: 331 Within the decade, Yale built chemistry, zoology, and botany laboratories, and new buildings for the Forestry School, and Peabody Museum, all in the Gothic Revival style popular at Yale in the early 20th century.^[16] The new facilities allowed Yale to demolish its older science buildings on its central campus, including the original Peabody Museum and Sloane Physical Laboratory, making room for the residential college system.^[17] Meanwhile, the Sachem's Wood mansion, preserved for the Hillhouse family in the purchase agreement, was increasingly surrounded by large laboratory facilities. After the death of the last Hillhouse heir, Yale demolished the mansion in 1942.^[7]

Expansion of science facilities (1945–present)

After World War II, residential overcrowding and an influx of married students prompted Yale to build temporary quonset huts on undeveloped areas of Pierson-Sage Square.^[12]: 406 The advent of the "atomic age" prompted a second period of laboratory building.^[18] University president A. Whitney Griswold relied on modernist architects for these facilities, breaking with pre-war gothic fervor.^[19]: 53 He asked Paul Schweikher for a Gibbs Laboratory design, Eero Saarinen for Ingalls Rink, and Philip Johnson for the Kline Biology Tower, Chemistry Laboratory, and Geology Building. Like Olmsted and Rogers, Saarinen and Johnson were also asked to improve the site plan. Saarinen's vision contributed modestly to the configuration, while Johnson's buildings gave Science Hill a central courtyard.^{[15]: 144 [20]}

In 1966, the construction of Wright Nuclear Structure Laboratory (WNSL), named for Arthur W. Wright, allowed Yale to house the first emperor Van de Graaff particle accelerator.^[21][22] Once the most powerful accelerator of its type, it was decommissioned in 2011 as other particle research facilities became more useful to the field.^[23] In 2013, Karsten Heeger initiated a transformation of the WNSL accelerator facility into a state-of-the-art facility, research program, and community that is equipped to develop, build and use research instrumentation for experiments across the globe that investigate the invisible universe. The new Wright Lab opened officially in a public opening ceremony on May 16, 2017.^[24]

At the end of the 20th century, Yale President Rick Levin announced new investments in sciences and medicine.^[25][26] In the years following, the university has launched at least five major building and renovation projects, including new buildings for biology, chemistry, environmental science, and the Forestry School.^[27]