While other properties simply add square footage, 12151 Reagan Street redefines what is possible. Thoughtfully expanded and meticulously reimagined, this exceptional residence in the highly sought-after Rossmoor Highlands has evolved into one of the largest and most versatile homes available in Los Alamitos. Designed for multigenerational living, growing families, or anyone unwilling to compromise on space, it offers a floor plan rarely found in the area. As you enter, the open-concept layout leads to the heart of the home, where the expansive family room with soaring ceilings, dining area, and beautifully appointed kitchen come together seamlessly. A generous center island, brand-new appliances, oversized refrigerator, abundant cabinetry, and direct backyard access create a space designed for both daily living and entertaining. The private primary suite occupies its own dedicated wing of the home. Soaring ceilings create an incredible sense of openness while sliding glass doors provide direct access to the backyard. The ensuite features separate his-and-her vanities, a jetted soaking tub, walk-in shower, dedicated makeup vanity, and an impressive walk-in closet. A secondary primary suite with its own ensuite bathroom and walk-in closet offers outstanding flexibility for extended family, long-term guests, or older children. Three additional bedrooms complete the original portion of the home. Independent split-system heating and cooling serve both private suites, while the remaining bedrooms are serviced by their own central system. Outside, fresh landscaping and new sod provide a clean canvas for the next owner to make it their own. The backyard offers privacy, functionality, and plenty of space to enjoy California living. Located just steps from Orville Lewis Park, the Rossmoor Highlands is one of Los Alamitos' most beloved neighborhoods, where neighbors gather for evening walks and the community's celebrated Fourth of July festivities. Homes offering this level of living space, flexibility, and thoughtful design rarely become available in Los Alamitos.