Harrison Lake is a 105-acre lake located in northwest Ohio's Harrison Lake State Park, which encompasses 142 acres of wooded terrain amid gently rolling agricultural land. All types of boats are permitted on the lake, though motorized vessels must operate at no-wake speed, making it suitable for paddling.

The lake features multiple access points, including a boat ramp near the Marzolf Shelter. The western end of the lake is notably shallow and offers opportunities to observe wildlife, particularly great blue herons and common egrets. The lake's shoreline includes both wooded sections and open areas, with approximately 3.5 miles of hiking trails providing alternating views of the waterfront.

Built in 1941 through the damming of Mill Creek, Harrison Lake supports a diverse ecosystem. Paddlers can spot various wildlife including painted turtles, box turtles, and the uncommon thirteen-lined ground squirrel. The lake hosts numerous fish species including largemouth and smallmouth bass, crappie, bluegill, northern pike, and bullhead catfish.

Facilities for paddlers include multiple parking areas, restrooms, and picnic areas with tables and grills scattered throughout the park. A 150-foot swimming beach is available, though pets are restricted from this area. A separate dog swim area is located near the campground.

The lake's creation is tied to the region's history as part of the Great Black Swamp, which once covered much of northwest Ohio. While little remains of the original wetland, the park maintains several natural features associated with its swamp heritage.

The park is open daily from 6 AM to 11 PM, though visitors engaged in legitimate recreational activities may access the lake outside these hours. The park office can be reached at (419) 237-2593 for current conditions and regulations.