Health officials are not releasing where she lived or any other details to protect patient confidentiality.
"We are saddened by this young woman's death, and our thoughts go out to her family and friends," Solano County Deputy Public Health Officer Dr. Michael Stacey said.
"While we are not seeing as many influenza cases as we were in the fall, there are still sporadic cases of flu circulating, and most of these circulating cases are H1N1," Stacey said.
The H1N1 vaccine is widely available. It will be distributed free at the House and Garden Show at the Nut Tree complex in Vacaville April 16-18.
Health officials are strongly recommending people get themselves and their children vaccinated. Children under age 9 require two doses for protection from the flu.
Health officials are also reminding the community to practice good hygiene by covering coughs and frequently washing hands.
The H1N1 flu first surfaced in the country in the spring of 2009. The majority of the cases in the nation and Solano County have been mild but the flu can be deadly in a small percentage of infected people.