The future of American Canyon’s only post office remains uncertain.

On Tuesday, the Napa County Board of Supervisors unanimously voted to send a letter to the U.S. Postal Service to keep the post office open.

“I think it really serves a huge need,” said Keith Caldwell, the Napa County supervisor who represents American Canyon.

The American Canyon post office branch is one of 413 nationwide the U.S. Postal Service may close to stem a $7 billion budget deficit. While the American Canyon branch remains on the list of post offices that could shut down later this year, another 2,800 candidates for closure early August have been spared.

In his letter, Mark Luce, chairman of the Napa County Board of Supervisors, cited American Canyon’s sharp population increase over the years. The city has about 17,000 residents.

“The American Canyon Post Office serves a very high volume of customers, many who must often wait in line outside in the rain, heat and cold because of the building’s small, 200-square-foot size. If this post office closes, American Canyon residents, many who currently live within walking distance of the building, will now have to cross county lines via highway to access the next closest post office, which is over five miles away in the City of Vallejo,” Luce said in his letter to John Potter, post master general and chief executive officer for the U.S. Postal Service.

American Canyon’s post office is inside a portable building from the 1984 Summer Olympics in Los Angeles. It opened on Crawford Way in 2001 about a year after the city received its first ZIP code. Until then, Napa County’s second biggest city shared a ZIP code with Vallejo. 

American Canyon City Council members Joan Bennett and Ed West, two longtime American Canyon residents,  reiterated on Friday the need for American Canyon to have a post office.

“For our community, it’s very important,” Bennett said.

West said there is always a line at the post office, adding he cannot understand how the Postal Service can conclude the branch is not economically viable given its low rent. The federal agency pays $1 a year to lease the Crawford Way parcel from the city for the post office.

“I don’t think it makes sense,” West said.

Walk-in revenues at American Canyon’s branch totaled about $407,000 in 2008, according to the U.S. Postal Service.

Augustine Ruiz, spokesman for the U.S. Postal Service, said the post office is part of Vallejo’s distribution area.

“That’s the root of the whole problem” said Lori Luporini, the city’s former mayor who strongly backed the city’s efforts to have its own ZIP code and post office.

American Canyon is a city in Napa County, not Vallejo, said Luporini, adding perhaps the city should adopt an Upvalley ZIP code to make its point.

“The citizens of American Canyon are going to have to stand up,” Luporini said.

On Monday, chamber members and other volunteers will seek signatures from residents to keep the branch open, said Pam Wilkinson, president and chief executive officer of American Canyon’s Chamber of Commerce.

City officials have sought help from U.S. Rep. Mike Thompson, D-St. Helena.

In a written statement issued Friday, Thompson said, “The citizens of American Canyon are extremely dependent on the post office, because there are no easily accessible alternatives.”

 “I’ve been in contact with the Postal Service to let them know how important the American Canyon post office branch is to our community, and they have assured me that they are only in the initial stages of a comprehensive review.  I will continue to work for the people of American Canyon to keep the post office open,” Thompson said.

American Canyon’s branch is one 22 post offices that could close within the Bay Valley district, which stretches from the East Bay to Big Sur. An announcement will probably be made the first week in October, Ruiz said. The public will have the chance to comment for a period of 30 days once the U.S. Postal Service determines a retail center should be consolidated.