4BD/4.5BA (POTENTIAL 5BD) HISTORIC DEEPWELL ESTATE on FEE SIMPLE LAND. Representing a rare UNICORN OPPORTUNITY in SOUTH PALM SPRINGS, 1109 E. Mesquite spans a massive 20,909 SF PREMIER LOT in the prestigious DEEPWELL enclave. This 1957 MID-CENTURY MODERN pedigree blends expansive INTERIOR square footage with a FULLY DETACHED GUEST HOUSE, offering a PRIME canvas in a neighborhood where sales consistently reach the MULTI-MILLION-DOLLAR mark. The main residence is designed for the ultimate INDOOR-OUTDOOR LIFESTYLE, anchored by an OPEN-CONCEPT kitchen and living room with a dramatic DOUBLE-SIDED FIREPLACE opening directly to the SOUTH-FACING POOL and sweeping MOUNTAIN VIEWS. The PRIMARY RETREAT features direct SEAMLESS ACCESS to the pool and backyard, serving as a private sanctuary with a personal lounge, DEDICATED HOME OFFICE, and SPA-INSPIRED BATH. The FLEX SPACE: this cavernous bedroom with PRIVATE STREET ACCESS and an adjacent bath is ideal for a high-end studio, home gym, or NEXT-GEN GUEST SUITE, and can easily be CONVERTED INTO 2 BEDROOMS. On the opposite wing, find an additional GUEST SUITE with DIRECT POOL ACCESS and a full bath that doubles as a convenient POOL BATH with its own EXTERIOR ENTRANCE. The DETACHED GUEST RESIDENCE (CASITA) is a 1960s GLAMOUR time capsule featuring a PRIVATE ENTRANCE, DEDICATED DRIVEWAY, living/dining area, kitchen, and bedroom with MOUNTAIN VIEWS. A separate laundry closet ensures this AUTONOMOUS space offers the POTENTIAL to become an ULTRA-LUXURY CASITA for MAXIMUM PASSIVE INCOME. The oversized RESORT-STYLE OUTDOOR OASIS features a PREMIUM SOUTH-FACING orientation for MAXIMUM WINTER SUN, framed by INSPIRING MOUNTAIN VIEWS, the iconic KIDNEY-SHAPED MID-CENTURY MODERN POOL, and mature palms, offering PRIME VERSATILE SPACE to CURATE BESPOKE OUTDOOR LIVING with the POTENTIAL for a PROFESSIONAL OUTDOOR KITCHEN, AL FRESCO DINING, and PRIVATE POOL CABANAS. Rare for the area, this property boasts TWO SEPARATE 2-CAR GARAGES (4 covered spac