The mail into and out of Supai Village at the bottom of the Grand Canyon is likely to still be delivered by mule.
But the village post office may give way to a postal station at the community store or in tribal offices.
That's the word from the U.S. Postal Service, which included Supai on a list of 11 postal sites in Arizona for possible closure or conversion to a limited-service retail outlet.
The sites, mostly smaller rural branches or stations with low mail volume, are among more than 3,500 sites under study nationally as the Postal Service struggles to cope with sagging mail volumes and revenue.
But the post office in Supai, which is the capital village of the Havasupai Tribe, is unique -- it is the only one in the United States served by mule train. The village is reachable from the rim of the Grand Canyon via an 8-mile foot trail, although it is also now served by regular helicopter service.
The village is famous for the nearby azure-blue pools beneath a series of stunning waterfalls. Backpackers at the end of their stay regularly use the postal service to mail out their heavy packs parcel post rather than carry them out of the canyon.
The other postal sites in Arizona listed for possible closure are:
-- Mount Lemmon
-- Bisbee (Warren Station)
-- Sasabe and Topawa, both on the Tohono O'odham Indian Reservation
-- Blue, in Greenlee County
-- Bullhead City (Highway Station)
-- McNary, on the Fort Apache Indian Reservation
-- Oatman, in Mohave County
-- Valley Farms, between Florence and Coolidge
-- Wikieup, southeast of Kingman.
"They're all under study at this point, but that doesn't necessarily mean these locations will close," said Peter Hass, spokesman for the Postal Service in Phoenix.
Nationwide, the financially troubled Postal Service announced that it will study 3,653 local offices, branches and stations for possible closure. The post office operates 31,871 retail outlets across the country, down from 38,000 a decade ago.
Including such sites and automated postal kiosks, postal services are available at nearly 100,000 locations nationwide, the agency says.
The post office announced in January it was reviewing 1,400 offices for possible closure. So far, 280 have been closed and 200 have finished the review process and will remain open.
Once an office is selected for a review, people served by that office will have 60 days to file their comments. If an office is to be closed, they will be able to appeal to the independent Postal Regulatory Commission.
"We don't get any tax money, we're trying to operate within our means, the best we can," Hass said, noting that mail volume has dropped 20 percent over the last four years.
In addition, the recession resulted in a decline in advertising mail, and the agency lost $8 billion last year.
Arizona Daily Star Assistant Business Editor David Wichner contributed to this story.