The Halloween wedding of Teresa-Catherine Antoinette Deleski and Gabriel Peguero, of Magnolia, N.J., was attended by a dozen guests. Or maybe more.

“One of the things that makes this fun is you never know how many uninvited guests are going to show up,” said Joanne Schwartz, who married five couples Oct. 31 at the Burlington County Prison Museum in Mount Holly, N.J.

Ms. Schwartz, the Burlington County clerk, says the building, where murderers, bigamists and horse thieves once languished, is haunted. “A number of people have heard strange noises,” she said. “Many have had the feeling they’re being followed.”

In previous years, the county has offered free Halloween wedding services at the prison museum, which was built in 1811 and closed in 1965, but Ms. Schwartz said this was the first year anyone signed up.

The setting, perhaps, accounts for why. Signage about public hangings in the yard — there were six from 1863 to 1906 — and famous inmates like Albert DeSalvo, later known as the Boston Strangler, informs visitors outside thick-walled cells whose iron bars still clang heavily.

But for Ms. Deleski, 23, and Mr. Peguero, 27, who met in August 2018, when she was working at a Dunkin’ Donuts and he was a clerk at a Family Dollar store across the street, a Halloween wedding was a dream come true.

“Gabriel was friends with one of my co-workers, and he’d come over and talk,” Ms. Deleski said. “We were always laughing.”

As she got to know him, she also got to know his drink order — a caramel iced latte with no whipped cream and extra caramel — and started making it for him free of charge. “Then I started finding reasons to go to the dollar store to see him,” she said. Within weeks, they were a couple.

“Basically, we fell in love with each other because our personalities match and she’s my soul mate,” Mr. Peguero said.

On July 21, at her baby shower — their son, Lukas Avery, was born in August — Mr. Peguero proposed, and Ms. Deleski said yes.

Being Ms. Deleski’s soul mate means knowing how much she loves Halloween, Mr. Peguero said. So when the couple went to get a marriage license in August and learned about the prison weddings, they signed up immediately.

On Oct. 31, Ms. Deleski and Mr. Peguero and their dozen wedding guests, including Lukas Avery, who was napping in his infant carrier, met Ms. Schwartz on the prison steps. Ms. Deleski wore a champagne-colored gown and held a feathered mask over her eyes. Mr. Peguero was dressed in a white button-down shirt and black chinos with a gold face mask. They were Belle and the Beast, from “Beauty and the Beast.”

“That’s my favorite Disney movie,” Ms. Deleski said. “In the beginning, there’s a masquerade ball.” This explained the masks. The opportunity to be wed as Belle was the realization of a childhood fantasy for Ms. Deleski.

“She’s so much like me: She’s odd, she’s a little different. And she loves to read,” Ms. Deleski said. Mostly, though, it was the Halloween aspect that had drawn her to the prison steps.

“I’m a superstitious person and I’ve always loved dressing up,” she said, after exchanging handwritten vows with Mr. Peguero and handing off her bouquet of fall-colored mums to her sister and maid of honor, Kelisey Paige Deleski. “For us, this was perfect.”

Perfection was not the goal of every couple Ms. Schwartz married on Halloween.

Karen Riggins, 58, and Jeffrey Weisinger, 54, of Beverly, N.J., didn’t plan to combine a Halloween celebration with their wedding. “We just chose the day,” said Ms. Riggins, who is a career coach. Mr. Weisinger is a youth therapist. “All of this was a surprise,” she said of the handful of costumed spectators who watched as Ms. Schwartz, in a witch costume, married them outside the museum.

Still, the trappings of the holiday came in handy. Ms. Riggins and Mr. Weisinger wanted to partake in the African-American tradition of jumping over a broom to symbolize sweeping away their single lives and leaping into the new, but they hadn’t remembered to bring a broom. So, using Ms. Schwartz’s witch costume prop, they jumped hand-in-hand toward the prison entryway, where the warden once sat.

No one, including the couple’s three wedding guests, Ms. Riggins’s parents and son, cared to speculate on the symbolism of starting a marriage steps outside a prison cell.

Samuel Yohannan and Mindy Miller of Bordentown, N.J. were more interested in having a quick, free wedding. Their marriage was also a way for Mr. Yohannan to get on Ms. Miller’s health insurance plan.

“Halloween is an easy day for us to remember, but we’re really doing it for the insurance,” said Ms. Miller, 45, who wore a banana costume — “So I would look appealing,” she said — and carried the couple’s rescue dog, Frazzle, for her ceremony inside the prison. Mr. Yohannan, 42, wore a white T-shirt and brown jeans.

Ms. Miller, an investigator with the state, and Mr. Yohannan, a pharmaceutical automator, plan to have a more formal wedding celebration next year, for which they might write vows and offer wedding cake.

For now, the Halloween wedding was a way to obtain a signed marriage certificate and a couple of laughs. “That’s why they call it wedlock,” said Mr. Yohannan, walking out of the prison.

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