Alpha Tau Omega (ΑΤΩ): 1924 - 2000, 2012 - present

The Pennsylvania Alpha Iota Chapter of Alpha Tau Omega (ATO) was founded in 1881 and is the oldest established fraternity at Muhlenberg College.

ATO's large house was built on the southwest corner of 23rd and Chew Streets in 1924 and has been occupied by members of the fraternity continuously since that time with the exception of 2000 - 2012 when the Chapter’s charter was revoked by the College for hazing violations.

Prior to the construction of Hillcrest House, ATO lived in a house located on South 14th Street in Allentown, but the exact address is unknown.