The Puente Hills Landfill - formerly America's largest and deepest - is ready for a new life: to be upcycled and recreated into Los angeles County's newest park.  Read more about the project below.

About  |  Location  |  Objectives  |  A 30+ Year Timeline  |  Panoramic Views | Trail Connections | Habitat Enhancement
Waste Education and Interpretation | Landfill Settling and Methane Gas  |  Site History  |  Upcycle + Recreate Defined  |   About the Team

About the Project

How do you transform America’s former largest land­fill into an inspiring site for reflection and recreation? How do you design for a landscape projected to shift and settle 125 feet over the course of the next several decades? 

The County of Los Angeles Department of Parks and Recreation, with Withers & Sandgren Landscape Architecture + Planning, are leading an expert team in a 1-1/2 year master plan to envision a new life for this imposing 500 foot-tall mountain built over 60+ years from 130 million tons of our collective waste.

The project entails planning for the conversion of approximately 115 acres within the 1,365-acre former landfill site and will include the preparation of an environmental impact report (EIR) to analyze the potential impacts of this change. The project will also include an extensive community outreach process that balances community desires for recreation, trails and open space, with critical wildlife corridor needs across the Puente-Chino Hills, and other identified needs such as ongoing operations and maintenance.  

Amidst challenges such as land settlement and methane gas collection pipelines, the Master Plan will potentially weave together interpretation, trail connections, recreation and habitat restoration. 

Project Location / Site Context

The proposed Puente Hills Landfill Park site, neighbors, and surrounding views

Map of the 25-mile service radius of the proposed Puente Hills Landfill Park

The Puente Hills Landfill is owned by the Sanitation Districts of Los Angeles County. Approximately 115 acres of fill areas (see following exhibit) of the 1,365 acre site is available for parkland to be designed, constructed and managed by the Los Angeles County Department of Parks and Recreation. 

The Puente Hills Landfill Park site borders native hillsides and canyons managed by the Puente Hills Habitat Preservation Authority to the south, as well as the Rose Hills Cemetery to the southwest. 

The site is located within the Fourth Supervisorial District of Los Angeles County and is bordered by the First Supervisorial District directly to the north.

Project Objectives

1. Park For All

Develop a “Park For All” that offers diverse, healthy, passive and active recreational experiences and programming for visitors of all ages, abilities, interests and backgrounds.

2. Unique Regional Destination

Develop a regional destination park which uniquely reflects the site’s history, urban-wildland location, scale and topography.

3. Range of Recreation and Outdoor Fitness

Develop a range of active and passive amenities to meet varied recreational demands and provide outdoor fitness opportunities to help address national trends related to inactivity, obesity and nature-deficit disorder.

4. Gateway to Nature for Diverse New Audiences

Attract diverse, new audiences, particularly underrepresented or disadvantaged populations, to inspire connection to outdoor activities, nature, and environmental stewardship.

5. Integrated Recreation and Habitat

Integrate active recreational facilities with natural habitats to enhance and sustain both the recreational and ecological functions of the park.

6. Wildlife Habitat Connectivity

Promote and support wildlife movement and habitat connectivity through the Puente Hills Significant Ecological Area (SEA), the Rio Hondo College Wildlife Sanctuary SEA and the San Gabriel River.

7. Environmental Sustainability

Demonstrate environmentally sustainable design and practices.

8. Multi-modal and Universal Accessibility

Provide multi-modal, universal access and circulation into and through the park to the extent feasible.

9. Education and Interpretation

Incorporate design elements for education and interpretation on the park’s unique landfill history and natural environmental features.

10. Captivating Trail Experience

Provide a captivating trail experience within the park which also alleviates the overuse and degradation of the adjacent trail network.

11. Public Health, Safety and Landfill Operations

Balance development of park facilities with landfill maintenance activities to protect public safety, water quality and meet the Sanitation Districts’ regulatory requirements.

12. Balance Multiple Objectives

Balance multiple project objectives in a manner that considers the complex site constraints, park needs of the overall region, and the competing interests and needs of adjacent entities.

A 30+ Year Timeline: Transforming a Landfill to a Park

Panorama view of the Western, Eastern and Southern Decks of the proposed Puente Hills Landfill Park


There are three primary areas available for park development: the Western Deck, the Eastern Deck and the Southern Deck. These "decks" comprise the currently available portions of the refuse-filled areas of the landfill that were covered with protective clay earthen caps (5 to 12 feet thick) after the landfill closed in October 2013.

The first area to open will be a small portion of the Western Area (40 acres), which was one of the first areas to be filled and has had the opportunity to settle over the longest period of time. It will be relatively stable and ready for development by around 2017-2019, but is expected to settle another 10 feet in the coming decades.

The Eastern Area (49 acres) and Southern Area (28 acres) are not projected to be ready for major development until around 2038-2048, when they have settled and become relatively stable.

The internal trash from the past decades will decompose and settle, reducing the overall height by as much as 120 feet over the next 30 years. Less intensive park development may be possible on the top decks of these areas in the interim.

Opportunities and Challenges

The Puente Hills Landfill Park Master Plan is a complex planning project with numerous opportunities, and also significant technical challenges. Here are just a few.

Panoramic Views | Trail Connections | Habitat Enhancement
Waste Education and Interpretation | Landfill Settling and Methane Gas

Opportunity: Panoramic Views

Panorama view overlooking the Western and Southern Decks of the proposed Puente Hills Landfill Park

Picnic overlook at the proposed Puente Hills Landfill Park

View to Downtown Los Angeles skyline from the proposed Puente Hills Landfill Park

 Open views arc across the San Gabriel Valley from the hilltop site.

Like the iconic Griffith Park and the popular Baldwin Hills in West Los Angeles (Culver City), the Puente Hills Landfill Park has the potential to be a great scenic destination for Eastern Los Angeles County and the San Gabriel Valley.


The impressive San Gabriel Mountain range rises sharply above the valley and is one of the world’s fastest rising mountain ranges. In the winter, Mt. Baldy (elev. 10,069') stands snow-capped. The San Gabriel River flows south, and the Emerald Necklace multi-use trail loop parallels the river.


Downtown Los Angeles’s skyline rises beyond the Montebello hills, with the Santa Monica Mountains in the distance.


The Puente-Chino Hills extend east, and views reach as far as Mt. San Jacinto (elev. 10,833), rising above Palm Springs.

Find more views in the Gallery.

Opportunity: Trail Connections

Map of trails in the Fourth Supervisorial District which connect through the proposed Puente Hills Landfill Park. Los Angeles County Department of Parks and Recreation.

A popular network of hiking, biking and equestrian trails fan out over the natural areas in this region. Today you can explore the Puente-Chino Hills through a variety of trails*, reach the panoramic views of the proposed park atop the Puente Hills Landfill via the Schabarum-Skyline Trail, and even continue along the San Gabriel River Trail north to the mountains, or south to the ocean. The proposed park has the opportunity to become a key destination from the surrounding trails with new trail loops featuring overlooks and views. The proposed park could also serve as a trail staging area and/or central hub for the network of trails in the area, offering on-site parking and possibly alleviating neighborhood trailhead parking pressures. 

*Trails maintained by the County of Los Angeles Department of Parks and Recreation and the Puente Hills Habitat Preservation Authority.

Opportunity: Habitat Enhancement

Map of County-designated Significant Ecological Areas which surround and overlap the proposed Puente Hills Landfill Park. Los Angeles County Department of Regional Planning.

"The Puente Hills SEA open space extends north and west from State Route 91 (SR91) in Orange and Riverside Counties to the Whittier Narrows reach of the San Gabriel River. The Puente-Chino Hills are a natural, physical link between the Santa Ana Mountains and the San Gabriel River. The San Gabriel River flows from and links to the San Gabriel Mountains. By virtue of these linkages ... the Puente/Chino Hills function as both an important wildlife linkage and resident habitat area for regional wildlife populations."

The Puente-Chino Hills are home to many special creatures and plants, and are a refuge of natural beauty and biological significance in a sea of urbanization. Nature surrounds the landfill and the Puente-Chino Hills wildlife corridor stretches about 26 miles southeast all the way to the Cleveland National Forest (almost 25,000 acres). Development of the hills, however, has pinched and threatened this crucial habitat corridor into smaller fragments of land. If wildlife are cut off and can no longer move freely through their natural range, the species will suffer and decline. They lose access to food, shelter, and mates.

The Department of Regional Planning has specially designated portions of the Puente-Chino Hills in the County of Los Angeles General Plan as Significant Ecological Areas (SEA) to protect critical habitat from being lost forever. The park project site boundary overlaps with portions of the Rio Hondo College Wildlife Sanctuary SEA and the Puente Hills SEA. The proposed park has a key opportunity to enhance native habitat, expand the wildlife corridor and strengthen local biodiversity.

Opportunity: Waste Education and Interpretation

Talk about a teachable moment. No discussion of park planning on America's Former Largest Landfill could be complete without addressing waste.

Here we have a unique opportunity and responsibility to examine the profound impacts of our modern disposable culture and its severe toll on our natural environment. These massive hills, some 40-stories tall, contain our collective trash.

As we strive to transform this place into a special destination, we can't ignore the fundamental issue -waste - that created this place. By promoting creative ways to reuse resources and tackling waste reduction through education and interpretation, Puente Hills Landfill Park can be a catalyst for change in Los Angeles County.

Take the Clean LA Pledge and Rethink L.A. These Los Angeles County Department of Public Works websites are great places to start.

Challenges: Landfill Settling & Methane Gas

Methane collection pipe network along slopes of Puente Hills Landfill

Methane collection pipe at Puente Hills Landfill

Puente Hills Landfill Gas-to-Energy Facility Phase II

Puente Hills Landfill Gas-to-Energy Facility Phase I

There are two main challenges to using a landfill for a park site: Ground settlement and gas production.  


Decomposing landfill trash loses about 25% of its volume over roughly 30 years, leading to the layers of trash shifting and settling "like cereal in a box" over time. This means that the newer landfill hills we see today will be roughly 25% lower in years to come. Older areas of the landfill which have been settling for decades are reaching their stable point. This decomposition process occurs because the organic trash in landfills such as yard waste and kitchen scraps break down over time. As they break down and get compacted, gases are released which are collected in pipes.

This amount of ongoing, inconsistent settling limits the types of development that can take place on on the surface in the near term.  Such settlement can cause foundations to break and sink, utility and irrigation pipes to burst, roads and paving to crack and heave, light poles to tilt, and sports fields to crumple. 

Landfill GASes

Gases are released as trash decomposes. The Puente Hills Landfill was an early pioneer of capturing methane gas from the landfill and converting it to energy. Miles of pipes in and around the landfills send the methane to Gas-to-Energy Facility Phase I and Phase II on site which generate 50 Megawatts (gross) of power, enough energy to power 70,000 homes.

Methane gas is flammable, and safety systems are in place to keep the site safe.


Facility engineers routinely monitor the landfill to meet State environmental regulations, including checking for surface cracks that indicate settling and gas escaping. Crews may use small or large earth-moving equipment to regrade the surface and seal up any cracks so that the gases continue flowing to the energy plant. The final park design and development will need to carefully consider these environmental control systems.

Site History

In the mid-1960s, when the closure of the Palos Verdes Landfill in the South Bay was anticipated, the Sanitation Districts identified the Puente Hills canyons site as a location to provide the long-term disposal capacity for the southern and eastern portions of Los Angeles County. The Sanitation Districts acquired the 1,214-acre Puente Hills site in June 1970, where 500 acres were being operated as the San Gabriel Valley Dump since 1957. The Sanitation Districts continued the operation of the site for solid waste disposal and renamed it the Puente Hills Landfill. In May 1981, the Sanitation Districts acquired land adjacent to the Puente Hills Landfill that enlarged the site to its present 1,365 acres.

In 1983, The Los Angeles County Department of Regional Planning approved Conditional Use Permit No. 2235-(1), which allowed for the continued operation and expansion of the Puente Hills Landfill. The land use permit required the Sanitation District to enter into an irrevocable agreement with the County of Los Angeles or alternate public agency) to designate the "fill" portions of the site as open space in perpetuity. The two entities entered into a Joint Powers Agreement (JPA) on April 28, 1987.

The JPA required the Sanitation District to offer the County portions of fill areas for park and recreation purposes after they were brought to finished or final elevation and grade and no longer needed for landfill operations. 

The JPA also acknowledged the Sanitation District’s need to operate and maintain the environmental control systems in the designated open space areas and that the park and any subsequent improvements would not impair the Sanitation District’s activities or systems that protect public health, safety, and the environment.

Over the years, the landfill has employed numerous innovative, environmental approaches including generating electricity from landfill gas, managing materials recovery and recycling programs, and acquiring and maintaining local native habitat as open space.

On October 31, 2013, the Puente Hills Landfill ceased operations after decades of receiving trash from homes and businesses in over 60 cities and unincorporated areas within Los Angeles County. 

Final protective clay earthen caps cover the fill areas at varying thicknesses of 5 to 12 feet, and prevent stormwater from infiltrating into the fill.

Although the Puente Hills Landfill is closed and no longer accepting trash, operations and post-closure maintenance will continue for 75+ years until the buried trash is fully settled and stable.

Read more under "Challenges: Landfill Settling & Methane Gas"

Upcycle + Recreate Defined

upcycle:   1. To transform by-products, waste materials, useless and/or unwanted products into new materials or products of better quality or for better environmental value : creative reuse

recreate:   1. To give new life or freshness to: refresh   2. To take recreation

About The Team

Lead Agency:  County of Los Angeles Department of Parks and Recreation
Prime Consultant:  Withers & Sandgren Landscape Architecture + Planning
Visioning:  Hillworks
Architecture:  Lehrer Architects
Planning:  AMEC Foster Wheeler
Environmental:  ECORP Consulting
Traffic:  Fehr & Peers
Geotechnical:  Ninyo & Moore
Air & Noise:  Kunzman Associates
Public Outreach:  Arellano AssociatesDay One, VPE
Civil Engineering:  PACE