Pena Adobe/Lagoon Valley Park spans 470 acres on Pena Adobe Road just off Interstate 80 between Vacaville and Fairfield, making it an easy stop if you’re passing through Solano County. The park is genuinely spacious—you’ll see the historic Pena Adobe home, barbecue areas, horseshoe pits, a multi-purpose field, and a small pond scattered across the property. The real draw for dogs is the network of hiking trails that wind through Lagoon Valley, offering views of the surrounding hills and the lagoon itself.

The trails here accommodate different fitness levels, so you can choose something short and easy or tackle longer routes. Your dog can walk unleashed in designated areas, though you’ll want to keep them leashed on main trails to be respectful of other visitors. The paths are well-maintained and relatively easy to navigate, even if you’re bringing an older dog or a younger pup still building stamina. Bring extra water—there’s plenty of shade along the trails, but especially on warm days your dog will appreciate a drink break. The designated picnic areas near the parking lots work well if you want to take a break midway through your hike, and you can settle your dog on the grass while you eat.

This is a working park with actual community use, not a dedicated dog park, so you’ll share space with hikers, families, and people on bikes. That means it feels less crowded than some heavily trafficked destinations, though you might encounter horses on the trails occasionally. The location is convenient if you’re traveling between Sacramento and the Bay Area and need to burn off some energy, or if you live in the greater Fairfield area and want a longer walk than a typical neighborhood loop. Parking is free and there’s plenty of it near the main facilities.