When Chrissy Economos and Gloria McCourtney heard that the last full-size Kmart in the mainland United States was closing down, they knew they had to pay their respects, even if the store was more than 1,300 miles away.

As the shelves were quickly emptying at the Kmart in Bridgehampton, N.Y., the two sisters remembered the one in Duluth, Minn., where they grew up. They went to that store as children in the 1980s with their mother and grandmother, who wrote poetry in the Kmart Cafe. They got their driver’s licenses there and killed time by wandering the aisles as teenagers. Ms. Economos bought her first pregnancy test there. And once they had their own children, the sisters would escape to Kmart for their “mom breaks.”

“We would regret it if we didn’t come,” Ms. McCourtney, 39, said.

Kmart was once America’s leading discount store, famous for its “Blue Light Specials” for in-store customers. “Attention Kmart shoppers!” became a catchphrase, uttered by Johnny Carson and Beetlejuice.

Now, at the Bridgehampton store, the announcements seemed stuck in a pandemic-era time warp: Shoppers were asked to stay safe by masking up and social distancing.

After decades of decline, Kmart has now largely disappeared, living on in comedy bits or classic films like “Rain Man,” where Dustin Hoffman’s character only gets his boxer shorts at Kmart in Cincinnati. The closure of the store in Bridgehampton on Oct. 20 will leave just one small store in Miami, crammed into what was once the garden center of a much larger Kmart, and a handful on Guam and the U.S. Virgin Islands.