The dog-friendly Pena Adobe Hill trail is a 3.2 out-and-back trail in Pena Adobe/Lagoon Valley Park just off Interstate 80 between Vacaville and Fairfield.
This moderately difficult hike climbs through cattle grazing areas with views of the surrounding hills and the lake. Dogs are welcome on the trail, are permitted to be off-leash in some areas.
The trail is open year-round. It can be muddy during the rainy season, but in spring the rolling hills are a verdant green and are dotted with California poppies in some areas.
The trailhead is located opposite the lake from the main parking area at Pena Adobe/Lagoon Valley Park. Go through the yellow gate to the main parking lot and pay the parking fee at the kiosk. Head towards the main road across from the lake to find the trailhead.
