Theta Delta Chi, the eleventh oldest of the college fraternities, was founded in 1847 at Union College in Schenectady, NY by six members of the class of 1849: William G. Akin, Abel Beach, Theodore Brown, Andrew H. Green, William Hyslop, and Samuel F. Wile. In 1849, Green and Akin along with Francis Martindale (the first initiate), organized the Beta Charge (later renamed Beta Proteron) at Ballston Law School. However, two years later the school itself moved and the new Charge was disbanded and the members put on Alpha’s rolls.

During the 1850’s Theta Delta Chi spread rapidly, adding Charges at Vermont, Rensselaer Polytechnic Institute, William and Mary, Virginia, Hobart, Wesleyan, Harvard, Brown, Bowdoin, Kenyon, Tufts, Washington and Jefferson, and North Carolina. Few of these remained active for long, although several were later revived. Kappa at Tufts (1856) presently enjoys the honor of being the oldest active Charge in continuous existence.

During the 1860’s new Charges, at, among other institutions, Lafayette and Rochester (1867), Hamilton (1868), and Dartmouth (1869), continued to be chartered at a pace that kept slightly ahead of attrition caused by Charges going inactive. The Civil War, however, severely weakened most Charges as men left for military service; many of the earliest Charges went inactive during this period, and expansion in the South ceased for a century.

Only after 1870 did Theta Delta Chi begin to acquire its present configuration. Westward expansion had traditionally been opposed by a large segment of the Fraternity, which worried that supervision and solidarity would suffer if Theta Delta Chi were to stray far from the East. The rise of the large state universities in the West, particularly in the Big Ten, eventually overcame that resistance and the Universities of Michigan, Minnesota, and Wisconsin welcomed Theta Delta Chi between 1889 and 1895. Further Midwest expansion included Illinois (1908) and Iowa State 1919). Berkeley (1900), Stanford (1903), the University of Washington (1913) and UCLA (1929) brought Theta Delta Chi in strength to the Pacific coast.

Expansion in the East during the 1870’s, 1880’s and 1890’s brought Charges to Cornell, Boston University, Wabash, CCNY, Columbia, Lehigh, Amherst, Yale, MIT, Williams, and George Washington. Pennsylvania (1915) was the last Eastern Charge to become active before World War I, although 1904 and 1910 saw the reactivation of the Southern Charges, Epsilon and Nu.

Theta Delta Chi became an International Fraternity with charterings at McGill (1901) and Toronto (1912).

The Great Depression and the Second World War saw a number of Charges go inactive and brought a halt to expansion. At its Centennial Convention in 1947, Theta Delta Chi stood at 28 Charges, a number that would begin to increase only in the 1950’s.