10. Phi Delta Theta (Phi Delt/Phi's)

Phi Delta Theta was founded on December 26, 1848 at Miami University in Ohio. Along with Beta Theta Pi and Sigma Chi, these three fraternities form the Miami Triad. Phi Delta Theta currently has approximately 185 chapters nationwide, with over 250,000 lifetime members. Their national philanthropy is the ALS Association.

Fun Fact: 3 Phi Delts have been NASA Astronauts. Can you name all three?

9. Sigma Nu (Sig Nu)

Sigma Nu was founded on January 1, 1869 at the Virginia Military Institute. Sigma Nu was founded on anti-hazing principles, and those principles have been continually upheld ever since. Sigma Nu currently has approximately 230 chapters nationwide, with over 230,000 lifetime members. Their national philanthropy is the Helping Hand Initiative.

Fun Fact: Sigma Nu has members that are quite famous in the sports world. New York Giants Quarterback, Eli Manning, and Miami Heat Team President, Pat Riley are both members of Sigma Nu.

8. Pi Kappa Phi (Pi Kapp)

One of the newest fraternities on this list, Pi Kappa Phi was founded on December 10, 1904 at the College of Charleston in South Carolina. Pi Kappa Phi's original name was Nu Phi, which stood for "Non Fraternity." Pi Kappa Phi has approximately 179 chapters nationwide, with over 110,000 lifetime members. Pi Kappa Phi is the only fraternity to own and operate its own philanthropy, The Ability Experience.

Fun Fact: Jimmy Tatro, the actor who played Rooster in "22 Jump Street", is a Pi Kapp from the University of Arizona. He is also known for his satirical frat life videos on his YouTube Channel.

7. Lambda Chi Alpha (Lambda Chi/LCA's)

Another young gun on this list, Lambda Chi Alpha was founded in 1909 at Boston University. Lambda Chi Alpha has two founding dates, March 22 and November 9. The founding of Lambda Chi Alpha still remains controversial to this very day. Lambda Chi Alpha has approximately 190-plus chapters nationwide, with over 280,000 lifetime members. Their national philanthropy is Feeding America.

Fun Fact: Lambda Chi is the fastest growing fraternity in the last century.

6. Pi Kappa Alpha (Pike)

Pi Kappa Alpha was founded on March 1, 1868 at the University of Virginia. Originally founded as a whites-only southern fraternity, Pike removed any restrictions related to race in 1964. Pi Kappa Alpha has approximately 220 chapters nationwide, with over 250,000 lifetime members. Pi Kappa Alpha does not have a national philanthropy, but still widely participates in multiple causes.

Fun Fact: Just like Sigma Nu, Pike has their fair share of famous athlete alumni, such as retired Florida State head football coach Bobby Bowden and retired NBA champion Horus Grant.

5. Sigma Phi Epsilon (SigEp/SPE)

Sigma Phi Epsilon was founded on November 1, 1901 at Richmond College (now known as the University of Richmond). SigEp is one of very few national organizations that has chosen to abolish the pledging process. Sigma Phi Epsilon has approximately 340 chapters nationwide, with over lifetime 315,000 members. Their national philanthropy is Big Brothers Big Sisters.

Fun Fact: SigEp claims to have over 200 fraternities houses nationwide, which would make that as the most fraternity houses out of any organization nationally.

4. Sigma Alpha Epsilon (SAE)

Sigma Alpha Epsilon was founded on March 9, 1856 at the University of Alabama. Currently, it is the only fraternity that was founded in the Antebellum South, and it is one of the few greek organizations nationally that has chosen to eliminate the pledging process. Sigma Alpha Epsilon has approximately 300-plus chapters nationwide, with over lifetime 325,000 members. Sigma Alpha Epsilon does not have a national philanthropy, but still widely participates in multiple causes.

Fun Fact: Former Chicago Bulls and Los Angeles Lakers head coach, Phil Jackson, was an SAE.

3. Kappa Sigma (Kappa Sig/K-Sig)

Kappa Sigma was founded on December 10, 1869 at the University of Virginia. Kappa Sigma has one of the largest international headquarters in the fraternal world, which is located in Monticello, Virginia, home of Thomas Jefferson, and the University of Virginia. Kappa Sigma has approximately 300-plus chapters nationwide, with over 18,000 collegiate members. Their national philanthropy is A Greater Cause To Military Heroes.

Fun Fact: Kappa Sigma's motto translates in English as "Bologna Teaches".

2. Tau Kappa Epsilon (TEKE/TKE)

Tau Kappa Epsilon was founded on January 10, 1899 at Illinois Wesleyan University. Tau Kappa Epsilon was one the first fraternities to abolish hell week back in 1928. Tau Kappa Epsilon has approximately 270-plus chapters nationwide, with over 268,000 lifetime members. TKE's are extremely philanthropic and have joined forces with St. Jude Children's Research Hospital, the Alzheimer's Association, and Boy Scouts of America.

Fun Fact: Former U.S. President Ronald Reagan was a TKE at Eureka College.

1. Sigma Chi (Sig Chi/Sigs)

Sigma Chi was founded on June 28, 1855 at Miami University in Ohio. Sigma Chi is the second fraternity on this list that belongs to the Miami Triad. Sigma Chi has approximately 240-plus chapters nationwide, with over 300,000 lifetime members. In December 2012, Sigma Chi designated the Huntsman Cancer Foundation as its sole preferred philanthropic partner.

Fun Fact: On June 13, 2005, Sigma Chi was the first Greek-letter society to be honored by the United States Congress for the fraternity's 150th anniversary.