|Founded||March 4, 1827|
|Headquarters||P.O. Box 57417|
Tucson, AZ 85732-7417
The Sigma Phi Society (ΣΦ) was founded on the Fourth of March in the year 1827, on the campus of Union College as a part of the Union Triad in Schenectady, New York. It is the second Greek fraternal organization founded in the United States. The Sigma Phi Society was the first Greek organization to establish a chapter at another college, which occurred with the founding of the Beta of New York at Hamilton College in 1831, thus making it the first National Greek Organization. Sigma Phi is a member of the North American Interfraternity Conference.
Also of note, the Alpha chapter of Sigma Phi located at Union College has been in continuous operation since 1827 making it the oldest continuously running fraternity chapter in the United States.
The practices and rituals of the Sigma Phi Society are relatively unknown due to its establishment, and continued consideration, as a secret society.
Some of these own buildings on the National Register of Historic Places, such as the Sigma Phi Society of the Thorsen House in Berkeley, California. Chapters italicized are dormant. The Alpha of Michigan, Alpha of California, and Beta of New York have attempted, with varying success, to include non-men in the organization.