Rio Grande Mexican Restaurant, one of Boulder’s most iconic downtown haunts, will officially mark thirty-five years of operation this Saturday.

The Rio, 1101 Walnut St., is a popular gathering spot for students, locals and visitors. The restaurant serves casual fare south of the border, but may be best known for its boozy margaritas that fuel a wild weekend night on Pearl Street.

“The first rule of Rio Club is don’t talk about Rio Club,” said a customer at X.

Another customer recalled: “By midnight there was so much margin spilled on the floor that it was so sticky you could barely walk with your flip-flops on.”

However, the Rio, a key part of the Pearl Street district since 1989, has managed to survive the recession and pandemic. It has also outlasted countless other nearby restaurants and bars that have come and gone over the years.

There are five Rio locations scattered across the Front Range. The Boulder restaurant is the second-oldest establishment, behind the original restaurant in Fort Collins, which opened its doors in 1986. New locations later opened in Greeley (1996), downtown Denver (1999), and Park Meadows Mall in Lone Tree (2004).

Amber Betts, 44, grew up eating at the Fort Collins Rio with her family. Over the years he visited many different places and Rio became a beloved go-to destination for him, his family and friends. Even though some of their loved ones have moved away, they always make a trip there whenever they come to town to visit.

Betts said going to Rio was “nostalgic” for him. She loves salsa and dishes she remembers from years ago, but margaritas hold an extra special place in her heart.

“Obviously, margaritas are a big deal,” Betts said, laughing as he recalled the time he tried to replicate margaritas at home and paid the price the next day.

“This was a one-off incident. “It was like, ‘Okay, we’re never doing this again,’ because we were hungover,” he said. “It was stupid.”

This summer, Betts had a Rio margarita tattooed on rocks in memory of his mother, who passed away last year and who also loved the restaurant.

“That was our job, drinking margaritas together,” he said. “It’s part of a piece: The sun and the moon, a cactus (because he lived in Arizona), and then a margarita. “I told my tattoo artist that I wanted it exactly Rio style,” he said. “He changed it. He took some liberties with the styling, but it’s pretty close. So we can say that this is a Rio border.”

Although Betts hasn’t visited the Rio in Boulder yet, he said it’s “incredible” that the place turns 35 this weekend.

Pat McGaughran, owner of the Rio restaurants, said the Boulder location has been a “neighborhood fixture” for years.

“Of course we love our connection with the university and the younger crowd from that area, but I really feel like we’ve found our place in Boulder with our customers who support us and the community that comes here on a regular basis. Rio (and that) has been a really great thing,” he told the Daily Camera.

Boulder Rio did not start at its current spot. It originally opened in a small space further east, just at the corner of 17th and Pearl streets, McGaughran said. Rio eventually purchased a larger location next door to the original location, but the restaurant experienced “disparities” with its neighbors in that area. It moved to the 11th and Walnut location in 1996.

“Local neighbors were not happy with people parking on the street. “This really became a parking issue because the city said, ‘We’re not going to create more parking downtown,'” he said. “Instead of conflicting with the neighborhood, we chose to create a park area. “It’s a location that’s more proportional to the crowd coming and going.”

The building that Rio has called home for the past 28 years has a unique story that McGaughran appreciates. It was originally a uniform in which horses were fed and ridden. Later, the area became a transportation hub and the building was converted into a car garage. McGaughran, a self-proclaimed “car geek,” kept Car & Truck Co.’s illuminated sign on the wall to celebrate the building’s history.

There were other restaurants there before Rio moved here in 1996. But since then, McGaughran said it has helped “keep the area alive” for many years. After much time, effort and persuasion, Rio became an even more popular destination when the restaurant finally convinced the city to open a rooftop patio.

A few years ago in Rio has undergone major renovations. McGaughran said there is wear and tear on the building that needs to be repaired. The bar, previously located at the back of the restaurant next to the kitchen, was moved to the main dining area and other changes were made to improve the flow and continuity of the floor space.

Other nearby restaurants and bars such as Old Chicago, Tahona Tequila Bistro, Walrus and Absinthe House have not stood the test of time. McGaughran said the pandemic has hit his restaurants hard, and it might have been difficult for them to stay in business if they hadn’t pivoted to delivering their food and margaritas.

But after all this time, he’s still glad to be in Boulder.

“We’ve seen some comings and goings over the years. We’re very happy that people still love coming here,” McGaughran said.

To celebrate its 35th anniversary, Boulder Rio will host a Día de los Muertos-themed party on Saturday from 4 to 9 p.m. People of all ages are invited to enjoy live music, games and prize draws from the AUPA Group. There is no charge for the party and reservations can be made on the day, but entry is not required.