Nearly one acre of prime residential land on Sierra Drive, located in the highly sought-after foothills of San Antonio Heights. This established community is renowned for its custom estates, mature tree-lined streets, scenic mountain views, and a sense of character and permanence rarely found in newer developments. This 39,000 SF property offers approximately 195 feet of frontage and extends roughly 260 feet in depth. The mostly level to gently rolling topography provides a versatile canvas for redevelopment or the creation of a custom estate. Zoned RS-14M under San Bernardino County. Included in the sale are 1.5 shares of the San Antonio Water Company, providing valuable irrigation capacity for landscaping or potential grove use. The site is currently improved with a 1916-era residence featuring 4 bedrooms and 2 bathrooms, along with a detached guest unit/ADU at the rear. The improvements require substantial repair, offering the opportunity to restore the existing structures or clear the site for new construction. No HOA. Located within the Upland Unified School District. Conveniently situated just minutes from the 210 Freeway, the Village of Claremont, and the extensive trail systems of the San Gabriel foothills.