IT’S usually easy to distinguish between clothes and costumes: either

Drawing the line between polish and pretension is trickier, especially when last year’s costume can be this year’s classic, and next year’s yawn. Just consider the steady infiltration of 19th-century haberdashery into the 21st-century wardrobe. Garment after garment has arrived on the scene that one might think more Gilbert and Sullivan than Bergdorf and Goodman, only to be taken up by the young beards.

Not long ago, big brass-buttoned military coats looked a bit extreme. So did high-button, high-lapel vests and slim tweed trousers. And so did guys who tucked said trousers into high, old-fashioned hunting boots. Now these clothes (along with those ever-present beards and mustaches) look like downtown defaults compared with fall runway looks like cardinal-red tailcoats at Ralph Lauren, capes and bowlers at Alexander McQueen and knee breeches at Robert Geller.

As with home design, where curio cases, taxidermy and other stylish clutter of the Victorian era have been taken up by young hipsters, many of today’s popular men’s styles have their roots in the late 19th century. There are the three-piece suits once favored by mustachioed Gilded Age bankers; the military greatcoats and boots of Union officers; and the henley undershirts, suspenders, plaid flannel shirts and stout drill trousers worn by plain, honest farmers.

Just ask Taavo Somer, whose restaurant Freemans, with its mounted animal heads and antique oil landscapes, has been one of the trend’s most active petri dishes (and who lives the fantasy sufficiently to enjoy shooting skeet on weekends upstate). Even his eyebrows went up recently when he saw a young man dressed in a bowler, cape, breeches and knee socks on the Lower East Side.

“We’ve already seen the comeback of the butcher and the baker,” he said. “Next thing is going to be a hipster candlestick maker.”

The antiquarian aesthetic is far-reaching, with tendrils in the worlds of art (as in the work of the fashionable painter Walton Ford, opening Thursday night at the Paul Kasmin Gallery in Chelsea) and film (as in “There Will Be Blood,” “The Prestige” and, next month, “Sherlock Holmes”). But it has made its deepest inroads in interior design and men’s fashion. Just as in the late 1990s, when mid-century Modernism seemingly infiltrated every apartment, men’s wear shop and restaurant, this messier, cozier and more idiosyncratic Victorian dandyism is now reaching into all sorts of fashionable spots.

It decks the dark wood-paneled walls of the trendy Jane Hotel and the Bowery Hotel and A-list-y restaurants like the Spotted Pig and the Breslin. Somehow the look seems even more sincere in Brooklyn eateries like Vinegar Hill House and Marlow & Sons and in antique shops like Obscura Antiques & Oddities in the East Village and Luddite in Williamsburg.

Similarly, the look’s most popular components — tweedy vests, woolen trousers, henley undershirts, dark wool ties, scratchy cotton shirts — appear to have an added dose of authenticity when unearthed in tucked-away shops like Amoskeag XX and Against Nature on the Lower East Side, or Hollander & Lexer in Brooklyn. Often they are made in New York by small labels like Engineered Garments and Freemans Sporting Club, Mr. Somer’s line.

The photographer Mitch Epstein, who lives near the Freemans shop on the Lower East Side, said that the store and its aesthetic had so won him over that he recently bought a charcoal-plaid three-piece suit. “These are not the kind of clothes I was wearing,” he said. “I’m more high modern. But there’s a comfort and quality in them, a respect for what you wear and how you appear to others, but in a way that’s not heavy-handed.”

Part of the appeal, in fact, is in how the clothes relate not to the runways or the estates of Europe, but to America’s heartland in ways that few fashions do. Country and city men alike have rediscovered old-school American brands like Filson, Orvis, L. L. Bean and Duluth Pack. Obsolete hobbies like wet-plate photography are finding new enthusiasts; long-outmoded farming practices are being revived. Even deer hunting with old-fashioned muzzleloaded rifles, which have to be loaded with gunpowder, a musket ball and a ramrod, has come back in force in some states.

Who knows, maybe the troublesome comeback of the North American beaver population will lead to a new appreciation of beaver-fur hats. They would be welcome at Paul Stuart, where beaver collars adorn greatcoats worthy of Andrew Carnegie, or at the Harlem workshop of the stylish hatter Rod Keenan, who has been selling bowlers, derbies and, this season, even a handful of top hats.