On the reservation of the Shinnecock Nation, about three miles west of Southampton Village, stands a house that is half-painted a juicy, glossy red. A circular sculpture — a mandala — composed of seashells collected from Hamptons beaches, lies near the front door, where it is disturbed only occasionally by deer or a wayward UPS delivery truck.

This is Ma’s House & BIPOC Art Studio, founded last August by Jeremy Dennis, a fine-art photographer and Shinnecock Nation tribe member. Mr. Dennis grew up and currently lives in the building, one of roughly 660 residents of the 800-acre reservation. Through donations, sweat equity and the kindness of handy relatives, he has transformed the house into a retreat, educational center and showcase for artists of color. But he still has work to do.

“We’re maybe halfway there,” he said about the renovation project.

The “Ma” of Ma’s House is Mr. Dennis’s grandmother, Loretta A. Silva, who died in 1998 at the age of 78. Built in the 1960s by her then-husband, Peter Silva (they later divorced), with wood collected from a demolished 1845 church building, the property started off as a single room and grew incrementally as it absorbed three generations of family members. Ms. Silva raised six children there, including Mr. Dennis’s mother, Denise Silva-Dennis, who became a multidisciplinary artist and teacher. Mr. Dennis, 31, lived there from birth until the age of 13, when he moved with his parents and older sister, Kelly, to another house on the reservation.

Before Ms. Silva died, she told her daughter that she wished that her home could be turned into a museum that preserved memories of her family and Native American heritage.

More than 20 years later, Ma’s House not only hosts lively exhibitions, workshops and game nights, but its residency program brings BIPOC artists to the reservation for a month at a time to do projects based on some aspect of Shinnecock culture.

Works by the 11 artists-in-residence to date are displayed throughout Ma’s House and grounds. The mandala, for instance, is by the Jamaican-born Pamella Allen, who arrived in October 2021. The whelk shells refer to the source material of traditional Shinnecock jewelry.

Mr. Dennis’s own artwork also concentrates on indigenous themes. Some of his digital photographs show men and women in stereotypical Plains Indian-style deerskin and beads bumping up against contemporary Hamptons people. In another project, he documented Long Island sites infused with Native American importance.

“Jeremy’s work explores the cultural significance of the Shinnecock Nation’s history in the Hamptons,” said Yaya Reyes, the founder of Art & Soul: Hamptons, a weekend festival celebrating BIPOC artists that opens on July 22. (Mr. Dennis will lead a private tour of Ma’s House on July 24.)

When Mr. Dennis first conceived Ma’s House, in 2020, as he was grounded by the pandemic, the building had been abandoned for several years and was decrepit. It gave off a “wet-dog” smell, he recalled, which turned out to be from a colony of squirrels nesting above the first-floor ceiling among acorn hoards.

Despite its terrible condition, he believed $50,000 would bring it back to life, given that he and his father, Avery Dennis, Jr., a builder, would do most of the work. About 400 donors contributed to a fund-raising campaign that brought in close to that amount. But Mr. Dennis soon learned that replacing the plumbing, which was on the brink of catastrophe, would eat the entire budget. A home improvement loan was out of the question — in cases of default, banks are forbidden from seizing collateral on Shinnecock land, effectively redlining the community. Mr. Dennis dug into his own pockets to make essential repairs and many cosmetic ones. So far, renovation costs have totaled about $130,000, he said.

But now the original 1960s front portion has new flooring and fresh drywall for displaying art. The corner kitchen has been remodeled and contains a little gift shop. An enclosed summer porch is a dining niche. And that metal pole in the middle of the living room is for structural support? Not exactly, Mr. Dennis said: It is for aerobic exercises performed by his live-in girlfriend, Brianna Lynn Hernández Baurichter, a multidisciplinary artist whose primary subject is grief. Visiting children love it, he added.

Double glass doors lead to a rear portion with an art-bedecked hallway dedicated to Shinnecock and family history. On the second floor is the residency room, its walls hung with colorful abstractions painted by Yanyan Huang (July 2021), based on the contours of Long Island and Shinnecock ancestral lands. Bookcases are filled with volumes on Native American history, anthropology and culture donated by the public library in nearby Sag Harbor.

The books continue into a little office that was Mr. Dennis’s childhood bedroom. It is furnished with a computer, a printer, a plaster bust of his father that Mr. Dennis made as a college art project and Ms. Hernandez’s Día de los Muertos altar paying tribute to departed relatives.

On the third floor, under the roof gable, is a large space that was Mrs. Silva’s bedroom and is now Ms. Hernández Baurichter’s studio. The light-soaked room with treetop views has somewhat uneven, blue-painted floors, giving it an oceangoing feeling as much as the quality of an aerie. “Apparently my grandfather Peter never used levels,” Mr. Dennis said. “You always feel like you’re leaning.”

Ma’s House also has a walkout basement that is being fixed up for visiting artists to use as studio space. (Family photos show it crammed with cousins during Christmas celebrations.) A few steps below that is a subbasement where Mr. Dennis had been horrified to find the remains of an uncle’s Harley-Davidson motorcycle, not to mention a 700-pound rusted iron furnace that required a small army of relatives to remove. The dirt floor was covered with cement, and the room now holds gym equipment.

A tour of the tree-studded surroundings came with a warning to watch out for ticks. Chickens will arrive later this year to eat them, but for now Mr. Dennis led the way gingerly to a pair of beehives in back of the house. The hives (and two years of beekeeping services) were a gift from Roger Waters, the Pink Floyd band founder, who lives in Southampton and has financially assisted the Shinnecock Nation through recent struggles with New York State.

Nearby, raised garden beds were being prepped for seedlings delivered by Sarah Chien, a dancer who recently moved from Brooklyn to work on Quail Hill Farm, in Amagansett. Ms. Chien hugged a box with surplus herbs and greens. “A lot of kale, celery. Winter savory? I don’t know. You’ll have to smell it and get used to it,” she told Mr. Dennis. “Thyme, chives, lettuce.” She lifted a little pot.

“And some very sad collards I think you could nurse back to health.”

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