Vacant 0.50-Acre Lot with Existing Garage + Approved ADU Potential. Calling all builders, visionaries, and buyers looking to create their dream home in coastal Portsmouth! This half-acre lot offers a rare opportunity: This very private fenced and tree lined lot is a vacant buildable parcel that already features an oversized barn-style two-car updated garage with a fully updated studio apartment above it, including a full bathroom, new flooring, working appliances, and mini-split HVAC. The structure has undergone significant upgrades by the current owner, including heavy insulation, new PVC siding, updated electrical, GFCI outlets, and fire-rated drywall — all done with permits. The studio unit is eligible to become an official Accessory Dwelling Unit (ADU) once a primary residence is constructed on the lot — a perfect setup for future rental income, multigenerational living, or flexible guest space. For those ready to build, conceptual architectural plans are already on file for a two-story, 3-bedroom home, and a 4-bedroom septic design has been submitted to the town and is currently under review. Public water is already connected. SO much leg work has thoughtfully been done for you. Don’t miss this rare blend of flexibility, infrastructure, and future potential — whether you're a builder or a homeowner ready to break ground. Ideally situated near scenic Indian Avenue, 202 Old Mill Lane offers a prime location with a short walk to publicly accessible Pebble Beach .