Triangle Headquarters


History of Triangle Headquarters

The building was built in 1912 by a grant from Andrew Carnegie at an all-inclusive construction cost of $8,520.  It was used as the Public Library for the Town of Plainfield from its opening in January 1913 until October 1968 when the newest township library was opened at its current location on Stafford Road.

The Carnegie Public Library building was purchased in 1968 by the Simmonds family who owned D&A Company, a steel construction and engineering company based in Plainfield, IN.  The Simmonds’ used the library building as their personal family home and converted the large open areas into comfortable living spaces where they resided for nearly 30 years.  In 1987, the Nees family purchased the home when the Simmonds’ retired.  The Nees’ left the structure virtually unchanged except for painting and wallpaper.

Triangle Fraternity purchased the building in 1997 and remodeled the building, restoring and preserving many of the building’s historical features.  Throughout the years Triangle National Headquarters has been located in the old Carnegie building many local citizens have asked for private tours of the old town library and in 2000 Triangle opened the building to the Friends of the Library for their annual open house tour.  Many former library patrons were thrilled to visit an old favorite.

The Carnegie Library building continues to stand as a historical treasure for the Town of Plainfield with school children passing by every spring and fall as they learn their local history.  Triangle is honored to serve as caretaker of this historical building.

Visiting the Headquarters

If you are in the area, we’d love for you to stop in for a tour. Office and museum tours can be arranged from 9:00 a.m. to 4:00 p.m. during the normal office hours of 9:00 a.m. to 5:00 p.m. You can schedule your visit by calling Director of Operations, Rhonda Halcomb at (317) 837-9640.


120 S. Center Street
Plainfield, IN 46168

Contact Information

Phone | (317) 837-9640
Fax     | (317) 837-9642

Office Hours

Monday through Friday | 9:00 a.m. – 5:00 p.m.
Plainfield, IN is located in the Eastern Time Zone

National Headquarters Address

120 S. Center Street
Plainfield, IN 46168
P | (317) 837-9640
F | (317) 837-9642

Office Hours

Monday through Friday
9 a.m. to 5 p.m. (Eastern)

Contact | Shop | Join | Give | Events | Magazine | Comments