If you ask people in the city of Mexicali, Mexico, about their most notable regional cuisine, they won’t say street tacos or mole. They’ll say Chinese food. There are as many as 200 Chinese restaurants in the city. North of the border, in Imperial County, the population is mostly Latino, but Chinese restaurants are packed. There are dishes in this region you won’t find anywhere else, and a history behind them that goes back more than 130 years.

The Salcedo family sits in a coveted booth at the Fortune Garden restaurant in the city of El Centro. The mother and three adult sisters are almost drooling, waiting for their food to show up. They come from Yuma, Arizona -- over an hour away -- twice a month just to eat here.

A huge side order arrives, light-yellow deep-fried chilies, a dish I’ve never seen. Then a salt-and-pepper fish, which the Salcedos describe as “Baja-style,” with lots of bell peppers, chilies and onions. But have you ever heard of “Baja-style” dishes in a Chinese restaurant?

Mayra Salcedo explains, “It’s like a fusion, Mexican ingredients with the Chinese. It’s very different than if you go to any other Chinese restaurant, Americanized Chinese restaurant.”

Her sister, Marta, carefully mixes Chinese mustard, a little spicy Sriracha and ketchup into a special only-in-Imperial-Valley dipping sauce for barbecue pork.

“When they order, they don’t say barbecue pork,” says Fortune Garden co-owner Jenissa Zhou. “They say carnitas, carnitas colorada.” That’s “red pork” in Spanish.

Zhou came to the U.S. from southern China, and her husband, Carlos, from Mexicali. From the time he was a teenager, he worked in Chinese restaurants there. She says they opened their first restaurant in Imperial County in 1990. It took her awhile to get used to her customers’ taste buds.

“You can see, every table they have lemon and hot sauce. In Chinese food we don’t eat lemon.”

Those fried yellow chilies on almost every table, chile asado, are served in a lemon sauce with lots of salt, kind of a margarita flavor. If you believe the rumors, some chefs marinate pork in tequila. And they serve pato asado, roast duck, with lots of cilantro.

It’s not just on the plates where cultures combine. In the Fortune Garden kitchen, the cooks speak to each other in Cantonese. The waiters speak Spanish and English.

There’s a specific reason for all of this, according to Professor Robert Chao Romero.

“The restaurants you see now are remnants of the Chinese population that used to fill the U.S./Mexico borderlands in Mexicali and in Baja California,” he says.

Romero teaches in both the Chicano Studies and Asian American Studies departments at UCLA, and wrote the book, "The Chinese in Mexico."

“The Chinese started to go to Mexico after the Chinese Exclusion Act was passed in the United States,” he says.

That was in 1882. The Chinese were the first ethnic group specifically singled out and banned from entry into the U.S. So tens of thousands went to Cuba, South America and Mexico.

“The Chinese invented undocumented immigration from Mexico,” says Romero, smuggling in with coyotes or guides hired to lead people across the border, “and smuggling with false papers, on boats and trains. The infrastructure for that was all invented by the Chinese.”

In fact, today’s Border Patrol grew out of the Mounted Guard of Chinese Inspectors, created to keep Chinese immigrants from entering the U.S. At the same time, the Mexican government welcomed Chinese immigrants to go to the sparsely populated border region, to work on farms and in mines and canals. Many Chinese immigrants settled in Mexicali, becoming grocers, merchants and restaurant owners. Others managed to smuggle across and make lives in the U.S., including Imperial County.

All that history plays out in the family of Edmund Gee, whom I meet at his house in the town of Brawley. He’s a leader in the Imperial County Chinese-American community. Gee tells me that his great-grandfather came over with a few others from his village in southern China, and tried to cross into Texas at the Rio Grande.

“Unfortunately, he got caught in El Paso and they sent him back,” says Gee.

Years later, in the 1930s, Gee’s father made it, probably using fake papers to come through San Francisco, and finding his way to Imperial County, where he started working at a restaurant. Edmund Gee ran a grocery store here for 43 years, and he’s co-owned a couple Chinese restaurants in the county.

Since Gee’s great-grandfather first tried to cross, the border has been closed off to some groups of people. For others it feels fluid. Above and below the border, Imperial is all one valley geographically, and in some ways culturally. People joke that Mexicali is the biggest city in Imperial County -- it just happens to be in Mexico. Edmund Gee says that the Chinese communities on both sides of the border have always been pretty tight, inviting each other to special events and holiday celebrations.

People in Imperial County told me that it’s common for groups to cross the border for office parties or family celebrations in big Mexicali Chinese restaurants. Every day, Mexican farmworkers with special passes cross the border to work in Imperial County fields. Some have the opposite commute.

A block from the border in Calexico, California, George Lim pulls up in a big truck and drives a few minutes, crossing the international border into Mexicali.

Lim lives in the U.S., but he helps run one of the oldest and most grand Chinese restaurants in Mexicali, called El Dragon. There, he goes by Jorge Lim. I ask him: Why not run a restaurant in the U.S., where he lives? He first cites the population: Mexicali has close to a million residents, while there are only 170,000 in all of Imperial County.

“Just doing the math going to have a lot more customers here in Mexico,” he explains, while negotiating the streets of Mexicali. “And I hate to say it, but people in Mexico are more sophisticated than in Imperial about Chinese food.”

That sophistication may come from the decades of people eating Chinese food here, with some Mexican flavors. Seventy years ago it was a necessity: Chinese cooks used Mexican ingredients like chilies, jicama and certain cuts of meat because that was what was available. Now it’s part of a culinary legacy. Like this new dish on the menu at El Dragon: arrachera beef served with asparagus and black bean sauce. Lim says that’s the best meat for tacos, a clear Mexican influence. “Asparagus could be both Chinese and Mexican, but the sauce, the black bean, that’s Chinese.”

I try out a kind of Mexican/Chinese/American hybrid: an egg roll with shrimp, cilantro and cream cheese that seems like it shouldn’t be good, but is. And at El Dragon, they put avocado in the fried rice.

George Lim’s father, Canuto, came to Mexicali in 1954, and he has developed many of El Dragon’s inventive dishes. He tells my reporting partner, Vickie Ly: “Most people who open or work in the restaurants came to Mexicali with previous experience cooking and serving Chinese food. When these experienced chefs come here and put their heads together to share their knowledge of the trade, the Chinese cuisine gets to be really good. There’s no better Chinese food than in Mexicali.”

George Lim says a few restaurant employees recently arrived here from China under a “special skills” category. That skill? Cooking Chinese cuisine. Lim says sometimes these Mexicali-trained chefs move up north, to work in Chinese restaurants in Imperial County.

“One of the goals is to go to the U.S., have a better life for you and for your kids, give ’em a better education, better opportunity, maybe earning dollars instead of pesos,” he says.

They are the same reasons that drew their ancestors here from southern China 130 years ago.

Vickie Ly helped report and translate for this story. Chris Hoff helped with sound design. The series California Foodways is supported in part by Cal Humanities. Reporter Lisa Morehouse produced it during a fellowship at Hedgebrook, a residency for women writers.