In Vacaville, the Lagoon Valley Loop at Peña Adobe Park is a solid 3-mile circuit that works well if you’re looking for an easy walk with your dog. The trail circles a calm lake and stays mostly flat, so it’s manageable even if your dog isn’t a serious hiker. You’ll see the water on one side and open grassland with low hills in the distance—nothing dramatic, but pleasant enough for a couple of hours outside.

The park itself is pretty straightforward. You park near the historic Peña Adobe, the old ranch building that gives the park its name, then head out on the loop trail. Dogs need to be leashed the whole way, which is standard for most public parks around here. The path is wide enough that you won’t feel cramped when other hikers pass by, and it’s shaded in some spots, though there are stretches in full sun so bring water for both of you.

I went on a weekday morning in early fall and it was quiet—just a handful of other people out. On weekends it probably gets busier, especially once the weather cools down. The terrain is genuinely easy, mostly dirt and packed earth with minimal elevation change. If you have an older dog or one that’s still building endurance, this is the kind of walk where you won’t come home exhausted but you’ll still feel like you actually went somewhere.

The main thing to know is that it’s pretty exposed in places, so midday in summer can be hot. Early morning or late afternoon makes more sense if you’re visiting in the warmer months. Parking is free, and there are restrooms at the trailhead. It’s the kind of place you go when you want a reliable, no-hassle walk without driving far from town.