Lake Macbride State Park is gorgeous. It was definitely my favorite of all the places we visited during our three days in the Iowa City area. It's Iowa's largest state park and has 12 miles of trails. For more information on the park, I recommend this 1-minute Iowa Outdoors video.
Follow signs for the dam to find parking near the spillway. Alternatively, you can park at the beach and hike the 1-mile beach to dam trail.
After parking, it's a short walk to the spillway area.
The spillway is where Lake Macbride drains into Coralville Lake. I recommend water shoes for the spillway area, a series of short and shallow cascades. I saw many kids playing here.
Lake Macbride Boat Rentals has pontoons, pedal boats, kayaks, canoes and paddleboards. They're open from Memorial Day weekend through Labor Day weekend and located near the beach. I recommend checking the water quality before swimming at the beach. The beach is close to parking, a playground, concessions and restrooms.