This is two separate living units on one lot! Total size: 4 BR 3.5 BA; 2704 sqft. per county records; 1) Main House: 2187 sqft., 2)Accessory Dwelling Unit /Studio (ADU): 517 sqft. A large park-like setting in front of the home provides unobstructed views of San Pablo Bay and Mt. Tamalpais and wonderful bay breezes. The ADU has a separate entrance, kitchen, full bath, & separate HVAC. All kitchens, bathrooms and second-floor laundry have marble counters and backsplashs. Tile floors in main house, ADU kitchen and all bathrooms. ADU living room has LVP wood floors. There are two fireplaces, one large patio with redwood decking, one patio off the Master BR and a covered patio off the LR. Main House HVAC has 2 zones up and down. Mature landscaping on drip irrigation and exterior lighting. Remote operation of HVAC, locks, garage door, security and irrigation. Mare Island is a historic gem with wine tasting, brewery, whisky distillery, and ferry service from the island to San Francisco.