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Mason Regional Park
Photo courtesy of OC Parks.
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History

The land comprising Mason Park was originally part of Rancho San Joaquin. This rancho was granted to Jose Sepulveda in 1842 by the Mexican governor Alvarado. In 1864 the Rancho, consisting of 48,803 acres, was acquired by the firm of Irvine, Flint, Bixby and Company. The firm acquired another 59,381 acres with the purchase of Rancho Lomas de Santiago and a portion of the adjoining Rancho de Santa Ana. In 1876, James Irvine, Sr., bought out his partners to become sole owner of the vast rancho of over 100,000 acres.

The park, originally named University Park reflecting nearby U.C. Irvine, was renamed after William R. Mason, who served as President of the Irvine Company from 1966 until his untimely death in 1973. The Board of Supervisors changed the name of the park from University Regional Park to William R. Mason Regional Park in recognition of the impact his direction had and will continue to have on Orange County, not the least of which was the donation by the Irvine Company of land for this park. The first phase of the park, forty-five acres, opened to public use in 1973. A 50-acre second phase was completed in 1978. The second phase of development included a 9.2 acre lake which has proven to be a very popular attraction for park visitors.

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Organization

OC Parks

The 26-facility county parks system includes the Irvine Ranch Open Space, comprising Limestone Canyon, Weir Canyon and Fremont Canyon nature preserves, as well as Black Star Canyon Wilderness Park.

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Location

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Upcoming Activities

Join us at Mason Regional Park

Spot local native and seasonal resident birds with Laguna Canyon Foundation Volunteer naturalists on this slow and easy 2-mile hike through a landscaped suburban parkland setting at Mason Regional Park. No experience necessary! Age: 12 or older. Participants under 18...

Date:
Sat, 09/27/2025
Time:
8:00 am - 11:00 am
Where:
Mason Regional Park
Difficulty Rating:
2
Minimum Age:
12

The OC Parks Jr. Ranger Program encourages park guests to explore the outdoor world within OC Parks by developing a sense of belonging, becoming a part of nature and feeling empowered to be stewards of Orange County’s natural and cultural...

Date:
Fri, 11/07/2025
Time:
3:00 pm - 4:30 pm
Where:
Mason Regional Park
Difficulty Rating:
2
Minimum Age:
8

Join OC Park naturalists for story time and short hike with your little ones (ages 3-6) as we learn about snow! Age: 3-6 year-olds. Participants under 18 must be accompanied by a parent or guardian. Location: William R. Mason Regional Park. Please...

Date:
Thu, 12/18/2025
Time:
9:30 am - 10:30 am
Where:
Mason Regional Park
Difficulty Rating:
1
Minimum Age:
3
Family Friendly:
Yes
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