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Irwindale: Mining the Building Blocks of Los Angeles

The Raider Crater (cropped for header)
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Measuring 527 miles in length, freeways are one of the most important features of the man-made landscape in Los Angeles. But where does the material to make all of these freeways come from? Most of it comes from the City of Irwindale, a small suburb located 20 miles east of Los Angeles. In fact, today, when you drive along the 210 and 605 freeways through Irwindale, you can see the gigantic mining pits where the earth was removed to make much of L.A.’s freeways, along with other roads and structures. These pits form the economic backbone of this industrial city of only 1,422 residents and have played a major role throughout the city’s history.

Freeways of Irwindale
Irwindale and its freeways have a deep relationship. 1987 photo by Javier Mendoza, courtesy of the Herald-Examiner Collection – Los Angeles Public Library.

The area we now know as Irwindale has always been heavily influenced by its natural environment. During the mid-19th century, the area was part of the Rancho Azusa de Dalton but was not considered valuable because of the overabundance of rocks and sand. A ranch overseer, Gregorio Fraijo, settled his family on about one hundred acres of land near the present day intersection of Arrow Highway and Irwindale Avenue. The land was not suitable for orchards or grazing cattle, but the nearby San Gabriel River provided an abundant source of water, and corn was successfully cultivated on the land. The area became a safe haven for immigrants, many from Sonora. Members of the Fraijo family began to marry family members of Facundo Ayon, a friend of Fraijo’s from Sonora, and the Ayon family settled in the area. Generation after generation stayed on the land and today some native Irwindale residents can trace their descent back seven generations to the two families. A significant portion of Irwindale’s population is still related to each other through blood or marriage.

Over the years, several names were applied to the dusty and rock filled area: Sonora Town, Cactus Town, Spanish Town, and Jackrabbit Town. The name “Irwindale” first appeared at the end of the nineteenth century. Its origin is disputed. One theory holds that the city was named after a man whose last name was Irwin, who introduced a gasoline-powered pump to the area’s residents and then swindled them out of their rights to the San Gabriel River. Another theory suggests the name derives from California’s thirteenth governor (serving from 1875-1880), William Irwin, who was the namesake for a post office opened in the area in 1895. Regardless of the origin, the name “Irwindale” gained widespread usage during the 1920s.

The rapid development of Los Angeles after the turn of the century – its population grew tenfold from 1900 to 1930 – stimulated the need for new roads and buildings and, by extension, quality construction aggregate. Aggregate is a category of material used in construction, which includes crushed rock, gravel (naturally broken rock), and sand. Aggregate is also a component of composite materials such as concrete and asphalt. The seemingly limitless need for aggregate would forever transform the dusty little town of  Irwindale, which contains some of the highest quality and quantity of aggregate resources in all of Southern California.

Irwindale mining
Irwindale's Reliance Rock Plant in 2009. Photo by Gary Leonard, courtesy of the Industrial Los Angeles Collection – Los Angeles Public Library.
Irwindale mining
Conveyor belt at Irwindale's Reliance Rock Plant, 2009. Photo by Gary Leonard, courtesy of the Industrial Los Angeles Collection – Los Angeles Public Library.

Irwindale’s rich supply of aggregate comes from the San Gabriel River, which carries broken rock out of the nearby San Gabriel Mountains and deposits it in the city. The mountains produce an especially large amount of rock and gravel because they are very steep (steepness affects how much mud, gravel, and rock a river can carry) and earthquakes cause the mountains to grow (which counteracts the effects of erosion and helps maintain steepness). The San Gabriel River flattens out in Irwindale, which causes the debris that was carried by the river to settle out. Because of these natural factors, rock and gravel have been accumulating in Irwindale for thousands upon thousands of years.

The first commercial-scale aggregate production sites began operating out of Irwindale in 1900. Railroad lines and stations were built to ship a steady supply of aggregate to locations through Los Angeles County. And as the number of automobiles increased in Los Angeles, so did the demand for better roads – and thus the need for crushed rock and gravel. Irwindale’s rocks and gravel were also became part of many of L.A.’s best-known structures, including City Hall, the Biltmore Hotel, the Los Angeles Memorial Coliseum, Union Station, Dodger Stadium, the Bonaventure Hotel, and the Los Angeles Convention Center. otel,. HotedAnd when L.A. started building its first freeways, including the Arroyo Seco Parkway, materials mined from Irwindale were utilized. As Los Angeles grew, Irwindale’s mines flourished.

Mining became the town’s principal industry. Seventeen mining sites came to occupy 70 percent of the land in Irwindale. Interested in obtaining tax revenue from the mining operations, neighboring cities such as West Covina, Azusa, Baldwin Park, and Duarte began exploring the possibility of annexing Irwindale. Not wanting to be subjected to potentially higher taxes, the mining companies approached Irwindale’s local leaders about the idea of incorporating Irwindale as its own municipality. An election was held in 1957. Out of the 153 votes cast, 133 were for incorporation. Irwindale subsequently became the fifty-sixth incorporated city in the County of Los Angeles.

In the early days of cityhood, the mining companies dominated the local economy and wielded enormous influence. This influence can even be found in the shape of the city. Its zigzagging borders trace the boundaries of the mining companies that supported incorporation. During the 1970s, however, some of the quarries ceased operation and pits sat idle after they had been mined to the permitted depth of 200 feet. There was concern that the city would decline along with the gravel industry and become a wasteland of old mining craters. So Irwindale looked for ways to repurpose the unused pits after mining had ceased.

Irwindale: Home of the Raiders
Not quite. Photo by Javier Mendoza, courtesy of the Herald-Examiner Collection – Los Angeles Public Library.

In 1987, officials launched a bid to lure the Los Angeles Raiders professional football team to the small city, home at the time to 1,068 people. The thinking was that one of the abandoned pits next to the 210 freeway would be perfect for a 65,000 seat football stadium. In exchange for bringing a professional football team to Irwindale, the city promised to provide the land and loan the team $115 million – including $10 million in forfeitable cash – to construct the stadium, practice facilities, team headquarters, and a Raiders Hall of Fame. The Raiders’ owner, Al Davis, eventually took the team – as well as Irwindale’s $10 million – to Oakland. The pit where the stadium was supposed to be built became known as the Raider Crater.

Other ideas for the unused pits found more success. For example, the Irwindale Speedway opened in 1999 atop a former gravel pit – filled, ironically, with old tires from dump sites. And the Irwindale Business Center, a 2-million square foot industrial area, is currently rising from a former quarry. The project’s first phase was completed in 2001.

Seeking tax revenue sources outside of the mining industry, Irwindale has also aggressively courted and lured companies to move to the city.

In 1977, Irwindale sold a 238-acre property to Miller Brewing Company (now MillerCoors) for the sum of one dollar to build a brewery. In return, Irwindale receives tax revenues based upon the brewery’s production. Today, seven million barrels of beer a year are brewed in Irwindale, including Miller Lite, Coors Light, Miller High Life, Miller Genuine Draft, Keystone Light, Steel Reserve, and Mickey’s.

More recently, in 2013, Irwindale lured the famed Sriracha hot sauce maker, Huy Fong Foods, to build its $40-million Sriracha factory in the city by purchasing the property for the factory and offering the company a $15-million loan. In return, Huy Fong Foods reportedly agreed to contribute $250,000 a year to the city for ten years. Since then, a lawsuit brought by neighbors and the City of Irwindale complaining of jalapeno pepper and garlic odors generated by the factory has strained the city’s relationship with the hot sauce maker.

Despite attempts to diversify its economic base, Irwindale has not given up on mining. Six quarries remain active and city officials are currently negotiating with pit owners who want to dig deeper than the 200-foot limit. Some pit owners have proposed deepening their quarries by another 150 feet, which would add 30 years to the holes’ gravel-producing lives.

Today, as you speed along the 210 or 605 freeways through Irwindale, you can see the pits which supplied the raw material for the very road on which you are driving. It is one of the rare occasions in Southern California where you can experience the built environment while witnessing the scars it has left on the natural environment. Pieces of Irwindale – a billion tons of it – are spread throughout Los Angeles, in our freeways, roads and buildings. The pits in Irwindale are monuments to the immense amount of natural resources Los Angeles consumed as it grew from a small pueblo into a giant metropolis.

The Raider Crater
The Raider Crater today. Photo by Robert Petersen.


Arax, Mark. “Irwindale Oks $115-Million Raiders Loan.” Los Angeles Times, August 20, 1987: 3.

Arvizu, John. Eyes to the Past - A Pictorial History from Families of Azusa, Baldwin Park, and Irwindale, 2009.

Birkinshaw, Jack. “City’s Plan for Gravel Pits Questioned.” Los Angeles Times, September 30, 1976: 15.

Broggie, Michael. The History of Irwindale: Jardin de Roca (Garden of Rocks). Virginia Beach, VA: The Donning Company Publishers, 2011.

Chang, Irene. “Irwindale: A Little City’s Big Dreams Turn Sour.” Los Angeles Times, January 28, 1990: B1.

Chang, Irene. “Most Irwindale Residents Had Given Up Hope Long Ago.” Los Angeles Times, March 13, 1990: A19.

Cummings, Judith. “Raiders Moving to Los Angeles Suburb.” New York Times, August 22, 1987.

Durslag, Melvin. “Memory Lane Winds Through Irwindale.” Los Angeles Times, July 7, 1990: C4.

Favot, Sarah. “Sriracha hot sauce factory no longer considered a public nuisance in Irwindale.” Pasadena Star-News, May 28, 2014.

Katz, Jesse. “Raiders Still have a Home in Irwindale.” Los Angeles Times, December 15, 1990: B1.

Pool, Bob. “Holes in the Ground Help Fill the City Till.” Los Angeles Times, March 13, 2003: B2.

Sanchez, Jesus. “Irwindale Pulls Itself From the Pits.” Los Angels Times, May 6, 1984: SG1.

Sullivan, Ben. “In Irwindale, Big Plans for The Pits.” Los Angeles Times, July 3, 1990: B1.

City of Irwindale, General Plan Update, City of Irwindale, June 2008

“Brewing Locations.” Miller Coors. Accessed July 25, 2016.

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