.gov was one of the original six generic top-level domains (gTLDs) created by Internet RFC 920 in October 2004. The other generic top-level domains established at the same time were .org, .edu, .com, .mil, and temporary domain .arpa.
The .gov domain is administered by the General Services Administration (GSA), an independent agency of the U.S. federal government.
The U.S. is the only country that has a government-specific, top-level domain in addition to its country-code top-level domain. This is a result from the origins of the Internet as a U.S. federal government-sponsored research network. Other countries typically delegate a second-level domain for this purpose.