You'd better book early, though, because Lough Lannagh is becoming so famous that a local website got 3.8 million hits when it hit the news. Then the site had to close down because of threatened legal action, leaving www.castlebar.ie with nowhere to go.
People were devastated. "It's too sad! I love this site. I live in London, but was born and raised in Castlebar, have family and friends there, visit as often as I can.
"It provides photos of St Patrick's Day parades, Christmas lights, etc, in the event that sadly I can't be there, and I visit the site every day," one writer said.
Others agreed. "It means a great deal to me. I am very sorry. This site contributes so much to the community in the town and provides a very valuable link to those of us who no longer live there."
"I am totally devastated by the decision to close down," said another. "Like so many others who visited the website, this was a tie to the town where I was born. The website kept me so connected, no matter where I was living, which is currently in Texas."
What could make a lake so lethal? Sex, actually. People were reportedly doing it under the nearby trees, in bushes, at and near the waters (in it, too, perhaps). An unusual wet weather activity, you may be thinking.
A man objected. Tony Geraghty, a freesheet editor, witnessed this joie-de-vivre and wrote a cover story for The Mayo Echo, captioned "Castlebar Lake attracts hundreds of perverts".
Threads on castlebar.ie found his article offensive; Mr Geraghty found the threads offensive. One thing led to a legal other and the site closed.
The moderator was pessimistic. He thanked their many supporters but added that, "It is, however, no longer possible to run a website such as this on a voluntary basis on a server based in Ireland".
It's perfectly reasonable to object to hundreds of people doing it in broad daylight. They could catch their death of cold for a start. There might be issues of exhibitionism that put onlookers in a difficult position because there's a time and a place.
It's potentially depressing -- if people are making love in the afternoon and we're not, they're having a better work-life balance than us. What about damage to the environment, too? On second thoughts, there are worse pollutants.
What I forgot to tell you is that the sex in question was gay. Lough Lannagh's gorgeous shores hosted sexual exchanges between men, rather than between gay women (who tend to draw a more admiring audience).
This complicates things because since Máire Geoghegan-Quinn, a west-of-Irelander, decriminalised sex between men in 1993, it's been perfectly legal, provided you observe the social etiquette of all adult sex and not act indecently or abusively.
Should these men have been doing it in public rather than in private? Open-air sex has its merits, although you wouldn't want to have hay fever. But gay or straight, it can offend, which means you need to show respect before showing anything else.
Gay men just don't have enough private places to meet and greet in rural Ireland so Lough Lannagh offered a lover's lane to flirt safely with someone who wants you back. And there's the curiosity factor, sexual in itself. How lonely would you be otherwise? A friend who lives in an isolated area says he has almost no chance to meet romantic partners and has to travel to Dublin every few weeks to find some warmth and affection. (He also doesn't want to be known as the local 'queer'.)
How far we've come on respecting difference means reckoning his loneliness, as much as the 15th anniversary of Geoghegan-Quinn's class act and the 25th anniversary of Gay Pride, which will rock Ireland this month.
At almost 10pc of Ireland's population, gay people outnumber Irish speakers, but they might as well be speaking Mandarin for all the priority they get. Prejudice invades everyday speech. Calling someone 'gay' is a routine insult for any minor social gaff.
Unfortunately, Iris Robinson, MLA, spoke for many when she damned homosexuality recently -- but at least her husband, Peter, is First Minister of a statelet where gay people can symbolise their commitment in a civil union.
She may look prejudiced, yet down here prejudice is seriously restricting people's legal and economic lives. I wonder about walking by Lough Lannagh on a summer day, fresh western light dazzling the water, air lit with natural joy.
The backstory is that it has been known as a venue for killing yourself. Some died because they felt different - because they're gay.
If I am to stumble on someone unexpected, let them not be cold in death. Let them be making love, warming each other, celebrating human life.
One and all.