Every June, thousands of new high school graduates from the Washington area flock to the shore for a week of sand, sun and freedom. But police say these teenagers often run into trouble with alcohol poisoning, sexual assault, robbery and criminal records.

The June Bugs that descend on the Atlantic create an issue for beach towns up and down the coast. Officials want to get a financial jump-start to their summer season, but they are always looking to minimize the collateral damage that comes from playing host to a giant party for the underage set.

Dewey Beach, as part of an effort to upgrade its party-town reputation, has launched a multi-year campaign to reach out to families throughout Maryland, Delaware and Virginia. Town police warn seniors about the pitfalls of the postgraduate revelry and urge parents not to abdicate responsibility the moment their children receive diplomas.

“Parents may think: ‘What’s the big deal? We’re sending them to college soon anyway,’ ” Dewey Beach Police Sgt. Clifford Dempsey told 250 parents and seniors Monday evening at Walter Johnson High School in Montgomery County. But a beach town is nothing like a campus, he said, where resident assistants, campus security and class schedules help to keep teens in check.

The beach is an “uncontrolled environment” with a large concentration of kids, Dempsey said. “The binge drinking is horrible. Marijuana is in every house we go to. The pills? An absolute nightmare.”

The Delaware town has been trying to attract more families with child-friendly activities, rather than relying on revelers drawn to night life. “We really don’t want kids to come here and drink and go crazy. Bottom line, it’s illegal,” said Jim Dedes, acting town manager for Dewey Beach.

Ocean City police have sent out hundreds of DVDs to high schools and parent groups in recent years outlining responsible behavior and relevant laws. The Maryland shore city also has a “Play it Safe” program with a list of free activities, including laser tag and paint ball, that comes with a free bus pass to keep teens off the road.

“Our goal is not to scare people from coming here,” said Jessica Waters, spokeswoman for the Ocean City police department. “Our goal is to get them down here and have them come back here every year.” But Waters acknowledged that it’s not always successful. There was a near-fatal car accident involving alcohol during senior week last year.

Dewey Beach’s scare-them-straight approach appears to be having some impact, town officials say. Notably, more parents are coming with children, renting houses nearby to keep an eye on them. In neighboring Rehoboth Beach, Police Chief Keith Banks said the outreach has helped tame the June visitors. The number of juvenile arrests or citations in Rehoboth Beach declined to 138 in 2011 from 203 the year before.

Montgomery parents have invited Dewey Beach police to the county for the past several years to help plan for beach week.

The meeting Monday at Walter Johnson, open to parents from several schools, was pitched as “an open discussion” about “the real story” behind beach week. The annual event is not endorsed by the school system or any individual school.

On a warm spring-like evening, the nearness of graduation felt palpable. Students wearing lacrosse shorts and and T-shirts emblazoned with logos of Cornell and Maryland chatted and laughed with friends and parents.

The mood strained after the lecture commenced. Dempsey and Lt. William Hocker described how police prepare for the arrival of underage drinkers each year with three patrol wagons that double as overflow jail cells and up to 30 additional seasonal officers.

Last year, the Dewey Beach police made 120 arrests for underage drinking. This year, they said, they have extra funding for overtime to enforce underage drinking laws.

The officers listed punishments for a range of infractions, including under-age drinking, underage possession of alcohol or drugs, breaking curfew, disorderly conduct, violating noise ordinances, loitering and jaywalking.

For 18-year-olds, such violations can lead to pricey fines or criminal records. For 17-year-olds, they could mean late night phone calls to parents who have to drive through the night to pick them up from jail, and then, months later, an appearance in a Delaware family court.

After the sobering session, students and parents split up to ask questions.

“Maybe this sounds naive, but where do they get the alcohol?” asked one parent. Dempsey said teens typically bring it in, sometimes filling huge suitcases with cases of beer. “They have it planned out in December how they will get the beer,” he said.

“How much fighting do you see down there?” another asked. “A lot,” Dempsey replied.

One parent said that it sounded as if the officer was advising them not to send their children at all.

“I can’t tell you not to let your kids go, but I would not want my daughter — she’s only 7 now — to be anywhere near that town,” Dempsey said. “My personal opinion: I don’t think it’s worth it.”

Afterwards, the organizers handed out talking points for parents and teens that covered relevant laws and responsibilities for rental property, along with a customizable pledge for seniors to sign that listed rules, such as no parties and no overnight guests.

“Kinda morbid,” said Walter Johnson senior Florian Bigot. “But I really want to go.”

Bigot and his friends had not found a house to rent yet, and his mother, Michelle Olive, remained undecided about whether he should go at all. She and a few other parents lingered in the folding chairs after the session, weighing the risks.

“We’re still talking,” she said.