In Tucson more than 100 vendors, known as hotdogueros, peddle Sonoran-style hot dogs — candy cane-wrapped in bacon, griddled until dog and bacon fuse, garnished with a kitchen sink of taco truck condiments and stuffed into split-top rolls that owe a debt to both Mexican bolillo loaves and grocery store hot dog buns.

Many, like Ruiz Hot-Dogs on Sixth Avenue, work step-side carts with two-item menus of Sonoran hot dogs and soft drinks. Set in dirt and gravel parking lots, beneath makeshift shelters, under mesquite tree arbors, these peripatetic vendors serve fast food for day laborers, craftsmen and policemen, the typical patrons of traditional hot dog stands in any town.

Other champions of the Sonoran style, like El Güero Canelo, with two Tucson outlets, have evolved from carts into full-scale restaurants. (At the Twelfth Avenue location, two of the three spaces where burritos, tacos and hot dogs are cooked and assembled remain on wheels, but the prospect of mobility is now far-fetched.)

One Sunday afternoon, as a mariachi band played, an after-church crowd, half Anglo and half Hispanic, thronged El Güero’s outdoor dining pavilion. Babies cried. Teenagers table-hopped. And parents argued that, rather than order a second hot dog, children should fill up at the salsa bar at the back of the pavilion, stocked with peeled cucumbers, sliced radishes and chunky guacamole. Front and center on every third table was a Sonoran hot dog.

For at least the last 40 years, likely longer, borderland vendors, in Tucson and elsewhere, have been refashioning the hot dog with a cloak of bacon, a clump of beans and a chop of tomatoes and onions, followed by squirts of mayonnaise, mustard and salsa verde. (Ketchup and other condiments show up, too. More recently, some vendors have begun offering a topping of crumbled potato chips.)

In a dozen or more cities across the United States, these Mexican takes on the American hot dog are ascendant — from Chicago to Denver to Los Angeles, where illegal street vendors selling so-called danger dogs to late-night crowds play hide-and-seek with the local health department.

Only in Tucson, however, do locals like Ms. Murillo cede hot dog provenance to Mexico. In Tucson, bacon-wrapped, Mexican-dressed hot dogs are not ascendant. They’re dominant.

A Mexican-American take on the hot dog aesthetic was relatively late to arrive. In 1940s Arizona, tamales were known, at least among speakers of colloquial English, as Mexican hot dogs. By the 1950s, true tamales were gaining mainstream status stateside, and American hot dogs had, more than likely, jumped the gate into Sonora and Baja and elsewhere.

The date at which bacon-wrapped hot dogs became known as Mexican hot dogs is unclear. The mystery deepens when you factor in that Sonora, one of the states most often cited as ground zero for bacon-wrapped hot dogs, is a locus for cattle ranching, not pig farming.

From the southern side of the border, numerous Mexico City origin tales emanate, some tied to feeding crowds at wrestling matches in the 1950s, others to feeding skyscraper construction workers during the same decade. (Daniel Contreras, owner of El Güero Canelo, cites a similar time frame, and tells just as plausible a story, but sets the action in his home state of Sonora, where a man he knew as Don Pancho worked the streets.)

As is the case with most folk dishes, its true crucible may never be pinpointed, but folkloric suppositions aside, the answer may be a simple matter of salesmanship:

By 1953, Oscar Mayer was running print ads, selling American consumers on the virtues of bacon-wrapped hot dogs. Perhaps Mexican consumers, inspired to emulate American dietary habits, took Oscar Mayer at its word, wrapping American-made hot dogs in American-made bacon, and claiming the resulting construction as their own.

One recent afternoon, at one of the two Oop’s hot dog stands he operates on Tucson’s south side, Martin Lizarraga sat beneath a tent-draped ramada anchored on one end by a flattop-equipped hot dog cart, and on the other end by a minivan painted with a hip hop-inspired, anthropomorphic hot dog character.

As a tripod-mounted speaker blared norteño music into the street, and toritos — mozzarella-stuffed, bacon-wrapped güerito chiles — browned and then blistered on the flattop, Mr. Lizarraga talked of the days when he worked as a liquor salesman in the Sonoran capital city of Hermosillo, frequenting the “table dancing club” for which he named his two hot dog stands.

With his 14-year-old daughter, Abigail Lizarraga, by his side, he spoke, with great enthusiasm, of Hermosillo, where “every corner has a hot dog stand” and “the health department is not so strict,” and vendors have the freedom to garnish a dog with everything from cucumbers in sour cream to crumbled chorizo.

Pressed to define the Sonoran hot dog, as served in Tucson, Mr. Lizarraga talked of the importance of the roll into which the dog is stuffed. (He buys his from Alejandro’s, where they bake a roll that is both soft and pleasantly pliant.) And he talked of the squeeze bottles of guacamole purée, with which he stocks both carts.

But Mr. Lizarraga did not mention the wrap of bacon, for that, in the world of the hotdoguero, is understood.