The San Bernard Oak is registered by the Texas Forest Service as the largest Live Oak (Quercus virginiana var. virginiana) in Texas.   This registration is based on the following measurements:   Circumference: 386 inches   Height: 67 feet   Crown: 100 feet Source: "Texas Big Tree Registry: Champion List for Species Native or Naturalized to Texas." Texas Forest Service. The San Bernard Oak is accessible from County Highway 306 via an unpaved driveway and a 0.6-mile hiking trail.   Parking is available at the north end of the driveway.   The hiking trail is relatively level, with several stretches of boardwalk over seasonal wetlands.   Hikers may observe a rich diversity of plants and birds, and evidence of many mammals. See the map below for location.   Scroll down for other maps and documents.