When Ann Marie Kennedy tried to update her Facebook profile in June, she naively assumed she could add her home town in a few simple clicks.

She is from Effin, Ireland.

Months later, Facebook still stubbornly refuses to accept the name of her birthplace. When she tries to update her home town, she is ambushed by similar-sounding options like Effingham, Ill., and Effingham, S.C.

“I’m a proud Effin woman,” said Kennedy, who is keen to connect with former residents. “There are other Effin people around the world, and they want to put down that Effin is their home town.”

Kennedy, 47, has launched an online campaign — on Facebook; she’s still a fan — hoping to prod the social-networking giant into allowing her and her friends to designate Effin as their home town.

The British Isles are littered with towns with seemingly offensive names, potentially paving a difficult path for online gatekeepers trying to stamp out vulgar language.

Appealing to a nation’s voracious appetite for puerile humor, Rob Bailey and Ed Hurst, the authors of the books “Rude UK” and “Rude Britain,” have compiled hundreds of names of places here that could be considered crass or boorish or just plain funny, including Crapstone, Slack Bottom, Golden Balls, Knob Field, Badgers Mount, Penistone, Foulridge and Ugley. (Of this random list, the last three are available as hometown options on Facebook.)

While the fondness here for double-entendres can’t be exaggerated enough, the names of many “rude” places date back hundreds of years to a time when no one would have sniggered at their mention, according to Bailey and Hurst. Foulridge, for instance, can be traced back to 1219 and alludes to “the place where fouls graze.” Pratt’s Bottom reportedly once referred to the bottom of the hill where the Pratt family lived.

Effin is a parish village of about 1,000 people and is known for its strong hurling team — an ancient Gaelic sport beloved by the Irish — and equally strong cheddar cheeses. Its name is said to date back hundreds of years and refer to a saint called Eimhin.

“Before cursing became popular, Effin was quite a normal word,” Kennedy said.

The places with seemingly offensive names are often mere wisps of town, and their omission on Facebook may have more to do with size than name. In the legal terms outlined by Facebook, users can’t provide false personal data, but there are no blanket bans against swearing. And there are many other disgruntled users whose online personas are homeless — the Facebook discussion page “My HOMETOWN is not listed, is yours?” has more than 400 posts.

In an e-mailed statement commenting on Kennedy’s case, Facebook said: “From time to time we are alerted to oversights such as this in our mapping system.”

Kennedy said she thinks her town was blacklisted because it sounds like a palatable alternative for a swear word.

She initially tried to launch a group on Facebook called “Facebook, Please recognise Effin, Co. Limerick as my Hometown,” but said she was rejected and directed to a page that said “this may be explicit or obscene.” When she removed the word “Facebook” from the title, her group page was suddenly accepted.

“My understanding of it was, I don’t think Facebook wants to be associated with the name Effin on the same line,” she said.

Kennedy, 47, now lives in a nearby parish called Banogue, where she works for the University of Limerick in its midwifery department, but she remains active in her native town.

“I play on the Effin badminton team and am directing ‘Effin Cinderella,’ ” she said, referring to a pantomime play, a popular art form here during the holiday season. She says she’s determined to move back one day and hopes to pen a book about the history of Effin. Residents joke about their town’s name, she said, but “we grew up with the name, so we don’t find it as funny as others.”

Last week she sent her profile page, the Google map location of Effin and other information on the Limerick area to Blue Rubicon, a London-based public relations firm working for Facebook. She’s hopeful that Facebook will recognize her home town soon.

“I just want to put down that I am from Effin because I am proud of my parish,” she said.