In the hills, flat land is currency, and this hidden Heath Terrace estate holds a fortune of it. Tucked behind mature trees in a private gated enclave most of Anaheim Hills has never seen, this nearly two-acre property offers something virtually unheard of in the hills: a completed ~4,400 sq ft Mediterranean residence with pool and spa in front, plus a completely flat back lot with preliminary plans prepared for lot separation, conceptual architectural plans included, and civil engineering completed to support development for a second home. This is the opportunity buyers wait years for and almost never find. Build a mini-mansion for extended family and create a true multi-generational compound. Develop and sell the second parcel. Or simply hold one of the last flat, buildable estate lots in Anaheim Hills as your private buffer. The optionality alone is the asset. The existing residence delivers immediately, with a gated private drive, an elegant foyer with sweeping wrought-iron staircase, 6 bedrooms, and 7 baths. It also features a true basement, a near-unicorn find in Anaheim Hills, ready to become a wine cellar, home theater, gym, or speakeasy-style lounge. Outside, the grounds function as a private resort. A pool and spa anchor the entertaining space, while the sheer flat acreage offers options almost no hills property can: room for a half basketball court, a removable pickleball court, and a lawn expansive enough to serve as a full soccer field for family games and gatherings. All of it sits minutes from Deer Canyon trails, Anaheim Hills Golf Course, the 91/241, and the area's well-regarded schools, including Canyon High School's International Baccalaureate program. Move-in-ready luxury today. A second estate tomorrow. Properties that offer both simply do not come to market in Anaheim Hills, and when they do, they don't wait.