Thornton A. Sullivan Park at Silver Lake is a 35-acre City of Everett park on the west shore of Silver Lake, in the south end of Everett about 5.5 miles from downtown along the Bothell-Everett Highway (SR 527). The lake covers roughly 104 acres, reaches 51 feet at its deepest point and averages about 24 feet. It sits entirely inside Everett city limits, and the park holds its main public swimming beach, a sandy strip looking southeast across the water.

The park address is 11405 Silver Lake Rd, Everett, WA 98208. Silver Lake Road runs along the park's west edge a few minutes east of I-5, and the paved lot off that road is a short walk from the sand. Everett Transit buses stop right at the park on Silver Lake Road (the stop is named Silver Lake Rd and Silver Lake Beach), which helps on hot weekends when the lot fills.

The beach is a wide stretch of sand that runs down to the water, with a buoy line marking the swim area in summer. There are no lifeguards. The city's park listing says plainly that no lifeguards are on duty, and it notes that loaner life jackets may be available at the beach. The water warms through July and August and stays cold in spring and fall, cold enough for hypothermia to be a real risk outside the summer months. Three small streams feed the lake from the north, the largest entering right at this park, and each year the city hires divers to hand-pull Eurasian watermilfoil so the swimming beaches stay clear of weeds.

Swimming is free. Everett charges no entry or parking fee here, and the park is open from 6 a.m. to dusk year-round. Restrooms are next to the beach, and the Silver Lake Beach Picnic Shelter sits just behind the sand. The park also has the Camp Patterson picnic shelter, a shelter by the docks and a building called Silver Hall.

The park's floating docks are where most of the trouble happens. Bystanders did CPR and the boy survived. Water off the docks is well over head height, so keep weak swimmers and small children in the roped area and in life jackets. Small boats share the lake, with motors limited to electric or low horsepower gas and a slow speed cap, so swim inside the buoys rather than out toward the middle.

Away from the water there is a large playground rebuilt by the city with a zip line and a rocking pirate ship, a disc golf course, wooded trails, a table tennis table near the beach and shoreline fishing. WDFW stocks the lake with rainbow trout, and yellow perch and rock bass are resident. There is no boat ramp, but paddlers carry kayaks to the water here or at Hauge Homestead Park on the lake's southeast side.