Snohomish County has many off-leash dog parks scattered around the county. Below are links on contact information for several of them.
Edmonds South Marina Park South of Marina Beach on Admiral Way. Follow signs to the Edmonds Ferry. Turn south on Admiral Way and follow road all the way to the end. The park is right on the beach and is a great place for water-loving dogs.
Everett Lowell Park 46th St. and S. 3rd Ave. This small park gets lots of visitors and is a great place to socialize your pups. Fresh water and poop bags available. Loganberry Lane Park 18th Ave. W. This park is a quaint, wooded off-leash area near Kasch Park by Paine Field. It's just over half and acre. Poop bags available, but you'll want to bring your own water. Parking is somewhat limited due to neighborhood construction. Directions: From I-5N heading towards Everett, take exit 189 for Hwy 526 towards Mukilteo/Boeing. Get off at the Evergreen Way exit and go left to head South. Turn right on 100th St SW. Go right again at Loganberry Lane. Continue straight to the end. Here's a map. Howarth Park 1127 Olympic Blvd.
Ebey Island There is no physical address, but the park is very easy to get to. If you've ever driven over the Highway 2 trestle to or from Lake Stevens and/or Monroe and/or Stevens Pass, Ebey Island is the agricultural community underneath the trestle. The general location is one mile east of I-5 and downtown Everett, on Ebey Island, and directly adjacent to the raised highway at 55th Avenue. Look for the orange fencing and the green entrance gate.
Gold Bar Gold Bar Off-Leash Area A small field on south side of Hwy 2, at Sixth St. on the way to Stevens Pass). Wheelchair accessible.
Lake Stevens Cavalero Hill Community Park Cavalero Hill Community Park is 2032 79th Ave. SE (corner of 20th and 79th). (If you go straight up the hill from Hewitt Avenue/U.S. 2, you can’t miss it.)
Monroe Wiggly Field The park is located at 413 Sky River Parkway in Sky River Park. Mountlake Terrace 53rd Ave West & 228th St SW, just northeast of the north parking lot of the Recreation Pavilion.
Snohomish Willis D. Tucker Community Park (11+ acres, close to Mill Creek)
Bothell Tambark Park This park will be roughly 3-5 acres of a 40-acre property at 17217 35th Ave. SE in Bothell.