Today, Penn State reaches every corner of the Commonwealth of Pennsylvania with 24 campuses, county Cooperative Extension offices and more. But in its infancy, Penn State could be found entirely within just one building.

The original Old Main building, completed at the site of today's structure in 1863 and first known simply as "Main Building," housed almost the entire operation of the school from classrooms, laboratories and offices to faculty and student living quarters and even animal housing.

The original Old Main was built of limestone from a quarry at what is now the southeast corner of Old Main Lawn. Work on the building began in 1857 with about 200 men participating in its construction, along with four mules and two horses that hauled limestone from the quarry. The most famous of those mules was Old Coaly, considered Penn State's original mascot.

Penn State expanded, but for nearly 70 years Old Main remained the administrative center of the school. By the 1920s, however, serious structural faults caused the upper floors of the building to be closed and in 1929 it was torn down. The limestone blocks of the original building were used in the construction of the new Old Main. Though only four floors, compared to the original's five, the new building had much more usable space.

For an aerial view of Old Main, present day, click here

Old Main continues to be the administrative center of the University today, with numerous offices including that of the President.

The upper walls of the lobby area are famous for artist Henry Varnum Poor's land-grant frescoes, a mural that pays tribute to the founding of the University and land-grant education. Poor finished the original work on the murals in 1940 and returned to extend the frescoes in 1949. In total, the mural covers 1,300 square feet.

The bell that hung in Old Main's bell tower was cast in 1871, and though the date it was installed is unknown, it was in use by 1892 and was a regulator of campus life until the new building was constructed. Though it was placed atop the new building, chimes took over the bell's role and the bell went largely unused. In 2009 the bell was removed from the tower and restored as part of the gift of the Class of 2009. The bell was then placed in a ground level display on the west side of Old Main in 2010.

Old Main Lawn, meanwhile, has been a hub for student activity since the school's opening. Over the years it has been used for recreation, concerts, festivals, rallies, and even a stage for presidential candidates. A stone at the southeast corner of the lawn commemorates the original quarry. At the base of the patio sits an armillary sphere, often mistaken for a sundial. Seven interlocking rings on the back of a turtle, it is an ancient astronomical instrument used to show positions of the rising and setting sun and was a gift of the class of 1966.