Editing Sigma Pi (section)

===Post War era: 1945 to 1980===
[[File:Schirra entering MA-8 capsule.jpg|thumb|Brother [[Wally Schirra]] entering capsule [[Mercury-Atlas 8|Sigma 7]] (1962)]]

Following [[World War II]], Sigma Pi benefited from increased college enrollments under the [[GI Bill]]. By 1950, it had 53 chapters (7 inactive), growing to 63 chapters by 1960. The Byron R. Lewis Educational Foundation, started in 1945 and incorporated in 1952, provided scholarships to members.<ref name = Emerald1987/><ref name = "Bairds1990" /> Beta-Kappa chapter at [[Arizona State University]], chartered in 1951, was unique for having founder James Thompson Kingsbury assist in its founding.

During the 1960s the fraternity added 39 chapters, reaching a total of 109. In 1961, [[Vincennes University]] donated the [[Shadowwood]] estate to the fraternity for use as its national headquarters.<ref name = offices/><ref name = "Bairds1990" /> The national office moved into Shadowwood in 1963 after renovations.<ref name=IBelieve />

In 1964, four chapters of the [[Delta Kappa]] fraternity joined Sigma Pi after being impacted by a 1953 [[New York State Board of Regents]] edict prohibiting national fraternities at state-funded universities.<ref name="Baird's_18th">{{cite book |author=<!--Staff writer(s); no by-line.--> |title= ''Baird's Manual of American College Fraternities''|url=https://books.google.com/books?id=35wQcgAACAAJ |location= Menasha, Wisconsin|publisher=Banta Publishing Company | editor-last=Robson | editor-first=John |pages=769–770 |edition=18th |date=1968 }}</ref>

William J. Cutbirth became the first Sigma Pi to be president of the [[North American Interfraternity Conference]], serving from 1974 to 1976.<ref>{{cite magazine|date=April 1929|volume=64|number=3|magazine=The Emerald of Sigma Pi|title=Three New Founders Awards Recipients|pages=5|url=http://www.enivation.com/SigmaPi/archive/Emerald/1976/SP_EMERALD_VOL_64_NO_3_FALL_1976.pdf|archive-url=https://web.archive.org/web/20170826031728/http://www.enivation.com/SigmaPi/archive/Emerald/1976/SP_EMERALD_VOL_64_NO_3_FALL_1976.pdf|url-status=usurped|archive-date=August 26, 2017}}</ref>