Chilmark Chocolates headed into its final weekend Thursday with a steady series of automobiles pulling up the driveway. Well before noon, the line of waiting customers stretched out the door and down the front steps of the modest building tucked off State Road just past Beetlebung Corner.

Inside the narrow retail shop, where half a dozen workers bustled to fill orders, customers lined up along the counter could see through the glass window to the candy kitchen that another nine or 10 people were dipping and shaping chocolates to keep up with the demand.

Ordinarily, Thursdays are the start of the shop’s four-day business week. But these are not ordinary times for Chilmark Chocolates. Owners Mary Beth Grady and Alison Burger have added Tuesday and Wednesday to the schedule for the final weeks before they close for good on Dec. 18.

Customers shopping this week mourned the impending loss of an Island institution treasured for more than three and a half decades.

Co-owner Alison Burger helps pack boxes during the last few days. — Albert O. Fischer 3rd

“This is what you always do before Christmas, before Easter, before Thanksgiving,” said Mary Brissette as she waited to enter the shop shortly before midday Thursday. “It’s just part of the Island tradition.”

“It’s the end of an era, that’s for sure, and not only because they make very good chocolates,” said Jim Pringle of Vineyard Haven after shopping Thursday morning.

“They do a world of good for people on the Island who are challenged a little bit,” he said.

For the more than 33 years they have owned Chilmark Chocolates, which they purchased from founder and fellow Camp Jabberwocky volunteer Jan Campbell, Ms. Grady and Ms. Burger have maintained a work force of up to 30 people, most of whom have some form of disability.

Autism, cerebral palsy, brain damage, blindness and developmental disabilities are among the challenges faced by Chilmark Chocolates staffers who work behind the counter, in the candy kitchen, or both.

Co-owner Mary Beth Grady continues her personal touch on Tuesday. — Albert O. Fischer 3rd

But it’s their abilities that Ms. Burger and Ms. Grady emphasize, said Rhiannon Maher, a member of the Mashpee Wampanoag tribe who commuted from the Cape to work weekends at the shop.

“The first thing they said is, what can you do?” recalled Ms. Maher, who wound up working the cash register, rolling truffles and stocking retail shelves with candy and gifts.

“I do everything that they ask of me, and I try to do it well,” she told the Gazette last year.

This tradition of inclusion, which has continued to Chilmark Chocolates’ final days, may account for the owners’ decision to close the company instead of selling it. It’s impossible to say for sure, as both Ms. Grady and Ms. Burger have a longstanding policy against granting interviews.

But they have been passing on their knowledge and techniques to longtime employee Sarah Flanders, who with her sister Allison recently completed a successful fundraising campaign to open a new up-Island chocolatier next year.

Handmade with love for 33 years. — Albert O. Fischer 3rd

“We hope that the girls that take over will do well,” said Margaret Maida, a Chilmark neighbor of the shop who knows both sisters.

“I think it’s going to take them a while to get going, but Sarah’s worked there a long time, and she’s a Flanders. She knows how important Chilmark Chocolates is to the town.”

Ms. Maida also praised Ms. Burger and Ms. Grady for their generosity in donating chocolates for any and every local cause that needed support.

“They’re just so active in the community,” she said. “We’re sad it’s closing, but we understand that [they] want to move on.”

Chilmark Chocolates is open from 11:30 a.m. to 4:30 p.m. through Dec. 15 and again on Dec. 17 and Dec. 18. Customers are limited to five pounds of boxed chocolates a week; small quantities in paper bags are exempt from the limit.

Advance orders have ended. A sign on the cash register advises: “We cannot use the same credit card more than once per day.”