CTAN (an acronym for "Comprehensive TeX Archive Network") is the authoritative place where TeX-related material and software can be found for download.
At a podium discussion that Joachim Schrod organized at the 1991 EuroTeX conference, the idea arose to bring together the separate collections.
(Joachim was interested in this topic because he is active in the TeX community since 1983 and ran one of the largest ftp servers in Germany at that time.)
The American site was first at Sam Houston State University under George Greenwade, in 1995 it moved to UMass Boston where it was run by Karl Berry.
Since 2021 there are four people who maintain the archives and the TeX catalogue updates: Erik Braun, Ina Dau, Manfred Lotz, and Petra Ruebe-Pugliese.