Walnut is a city in the eastern San Gabriel Valley of Los Angeles County, California, set on the southern slopes of the San Jose Hills. With a 2020 census population of about 28,400, it is a predominantly residential, single-family community known for its hillside neighborhoods, well-regarded schools, and a distinctly suburban, low-density character within the greater Los Angeles area. The city borders Diamond Bar to the east, West Covina to the north, and Pomona to the northeast, with the broader San Gabriel Valley and Inland Empire employment centers within reach. Walnut's history is rooted in agriculture. For more than a century, the area's fertile hills supported citrus and walnut groves, packing houses, and small farms, and the community that grew up around them took the walnut's name. Walnut incorporated as a city in 1959, transitioning over the following decades from ranchland into the master-planned residential community it is today, a transformation common across the postwar San Gabriel Valley. Two institutions anchor the city's identity. Mt. San Antonio College, founded in 1946 and located in Walnut since 1948, is one of the largest community colleges in California, serving tens of thousands of students across more than 400 degree and certificate programs on a 420-acre campus. The Walnut Valley Unified School District, which serves most of Walnut along with portions of Diamond Bar and West Covina, is consistently recognized for strong academic performance and is a central draw for families. Walnut is also a city shaped by its landscape. More than thirty miles of equestrian and hiking trails wind through its hillsides, connecting neighborhoods to county trails and reflecting the community's horse-friendly heritage. For homebuyers, Walnut offers a rare combination in the Los Angeles region: hillside and view homes, top-rated public schools, open space, and a calm, residential atmosphere within commuting distance of the region's major employment corridors.