Wizard's College of Mithila
The Wizard's College of Mithila is the largest such organization in The Whorl. Although there are colleges and guilds for arcane spellcasters in every community of large enough size to support a population of them, Mithila's College is widely acknowledged as the ur-example that all other such colleges aspire to.
Taking up a complex of improbably-tall spires in the heart of Videha, the population of professors, students, researchers, adjuncts, and visitors fluctuates into the thousands.
Although the College is technically a subsidiary organization of the Royal University of Mithila, the power and prestige of the College is such that it generally gets whatever funding and autonomy it needs. Nevertheless, its integration into the larger body means that there is a lot of cross-pollination of students from multiple disciplines, a practice that the University's Board of Regents, and Mithila's Council of the Wise, deem a great benefit for all who value the advancement of knowledge, both magical and otherwise.