Where did h1n1start?

Answer 1

The 2009 pandemic of Influenza A, Novel H1N1 "Swine Flu" was first detected in Mexico City and was made public March 18, 2009.

See the related question listed below for more details about other strains of H1N1 and when they were first identified.

Answer 2

Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a small fraction of all seasonal influenza. H1N1 strains caused a small percentage of all human flu infections in 2004-2005. Other strains of H1N1 are endemic in pigs (swine influenza) and in birds (avian influenza). Since it is endemic, it always is there. That means that it has been around for awhile and some say that it may have started in 1918 and cause a serious flu pandemic. But others say it has been around a very long time hiding in birds or pigs.

Answer 3

It appears to have begun in Mexico, last year (that is, 2009).

Answer 4

Mexico