Home Uncategorized Active Lots & Lands – Portola Valley – 94028 – San Mateo County – CA – 3/3 By siteeditor. Published on 29 1 月, 2014. Active Lots & Lands – Portola Valley – 94028 – San Mateo County – CA – 3/3 5900 ALPINE ROAD, Portola Valley 94028 Approx Lot: 198,198 Sqft Type: Single Family Residential Land Orig. Price: $698,000