Which came first, Facebook or the United States?

the United States came first, by 228 years. The Declaration of Independence was adopted.

Side by side

Facebook

Facebook launched on 4 February 2004 restricted to Harvard email addresses, opened to other universities through 2004 and 2005, and to anyone over 13 with an email address in September 2006. It is six years younger than Google and a year older than YouTube. Its predecessor Facemash, which compared students' photographs, was shut down by the university within days in 2003.

the United States

The date used here is the Declaration, 4 July 1776, which is the one people mean. Two others have equal claim: Britain recognised independence in 1783, and the Constitution took effect in 1789, so the current government is younger than the country by thirteen years. The United States is older as a state than Germany (1871), Italy (1861), Canada (1867) and modern Japan (1868).