This is a list of the oldest extant registered generic top-level domains used in the Domain Name System of the Internet.
Until 1986, Domain Registration was limited to organizations with access to ARPANET. The possibility of registration of UUCPNET, BITNET and CSNET hosts was announced in February 1986.
Registration within .edu is restricted to accredited educational institutions. Prior to October 2001, registration was available worldwide; it has since been limited to institutions based in the United States.