Harvard Yard is a grassy area of about twenty-five acres (0.1 km²), adjacent to Harvard Square in Cambridge, Massachusetts, that constitutes the oldest part and the center of the campus of Harvard University. Geographically the yard area is bordered to the west by Massachusetts Avenue and Peabody Street, the north by Cambridge Street, the northeast by Broadway, the east by Quincy Street, and the south by Harvard Street and Massachusetts Avenue. It contains thirteen of Harvard College's seventeen freshman dormitories, as well as four libraries, five buildings of classrooms and academic departments, and the central administrative offices of the Faculty of Arts and Sciences and the university, located in University Hall and Massachusetts Hall, respectively.
The western third of Harvard Yard, which opens onto Massachusetts Avenue at Johnston Gate, is known as the Old Yard, and around it cluster most of the freshman dormitories. Among these is Massachusetts Hall, which, having been constructed in 1720, is the oldest still-standing building on Harvard's campus and one of the two oldest academic buildings in the United States. The lower floors of Massachusetts Hall house the offices of the President of Harvard University.

Also located in the Old Yard is the statue of the university's first benefactor, John Harvard. This monument is a frequent target of pranks, hacks, and humorous decorations, such as the colorful lei shown at right, below. Moreover, Harvard students urinate on the very foot that tourists rub for good luck.
Facing Massachusetts Hall is Harvard Hall. The original Harvard Hall on this site housed the College library, including the books donated by John Harvard, after whom the college and the building were named—all but one of which were destroyed when the building burned in 1764. Rebuilt in 1766, Harvard Hall now houses classrooms.

Across the Old Yard from Johnston Gate stands University Hall, and the now-famous statue of John Harvard by Daniel Chester French. The statue has earned the nickname "the statue of three lies" from its inscription, "John Harvard, Founder, 1638". In truth, the statue is not modeled after John Harvard, Mr. Harvard did not found the university, and the founding was in 1636. University Hall was the site of the now-famous sit-in and teach-in protests during the late 1960s, while Massachusetts Hall was the site of the more recent 2001 living-wage campaign sit-in.

Other buildings

The center of Harvard Yard is a wide grassy area known as Tercentenary Theater, framed by the monumental Widener Library and Memorial Church. Harvard's annual commencement exercises, as well as occasional special convocations, take place in Tercentenary Theater.

The libraries located in Harvard Yard are Widener Library, its connected Pusey Library annex, Houghton Library for rare books and manuscripts, and Lamont Library, one of the undergraduate libraries. Classroom and departmental buildings include Emerson Hall, Sever Hall, Robinson Hall, and Boylston Hall.

The freshman dormitories of Harvard Yard include the upper levels of Massachusetts Hall, and Wigglesworth Hall, Weld Hall, Grays Hall, Matthews Hall, Straus Hall, Mower Hall, Hollis Hall, Stoughton Hall, Lionel Hall, Holworthy Hall, Canaday Hall, and Thayer Hall.
Nestled among Mower, Hollis, Lionel, and Stoughton Halls is the Holden Chapel, home of the Holden Choirs. Also in this section of the yard stands the Phillips Brooks House, designed by Alexander Wadsworth Longfellow, Jr., and home of the Phillips Brooks House Association (PBHA), Harvard University's center for service activities. At the southwest corner of the Yard is Lehman Hall, or Dudley House, the administrative unit for non-resident and off-campus students. Next to Lehman Hall is Wadsworth House, a canary-yellow building that houses the headquarters of the Harvard Alumni Association and the university library system. Finally, Loeb House sits on the east side; it is the site of Harvard's governing bodies, the Harvard Corporation and the Board of Overseers.

Below ground facilities

Harvard Yard is underpinned by a network of subterranean tunnels carrying people, steam heating and cooling, utilities, and other services across the Harvard campus. Observant students have taken notice of the effects these tunnels have had on the above-ground surface areas of the yard during winter.