One hundred years ago, a small but growing beach town called Willow Camp finally got a post office when a relative newcomer named Lyman DeCamp finally convinced the government to establish one. Up until then, mail was typically picked up by anyone passing through Bolinas and dropped off on the porch of a local store. But Mr. DeCamp got fed up after he found “a very important letter of his in the road, and it had been rained on and was open,” according to one of his daughters, Alice DeCamp Algar, in writings that the Stinson Beach Historical Society recently sent out in a special edition of its newsletter, the Willow Whistle. (Alice was the second postmistress, after the first, her sister, left the position.) But there was one problem. The government said there were too many post offices named Willow. So Mr. DeCamp suggested Stinson Beach, after Nathan Stinson, a landowner who ran a campground in the area for visitors. The post office was officially established on April 1, 1916. The town will celebrate the centennial with cake donated by the Stinson Volunteer Fire Department, food from the Parkside Café and beverages from the Stinson Beach Store. Marcus White, a clerk at the post office for 15 years, said that he loves the small, intimate quality of the Stinson outpost. “You get to see everyone,” he said. “Everyone’s nice, even the tourists. That helps a lot in a job like this. Post offices can be impersonal, but here it’s personal… it’s very enjoyable.” Mr. White is also the president of the historical society, but no one realized that the centennial was approaching until a few weeks ago, when historian Dewey Livingston came across the anniversary. “We thought it was an April Fools’ joke at first,” said Jim Harvey, Stinson’s postmaster.