Conneaut Lake is the largest natural lake in Pennsylvania by surface area. It is located in western Crawford County near a town with the same name. Its has a surface area of approximately 925 acres. The site of the lake is actually in adjacent Sadsbury Township and nearby Summit Township. During the summer season, it is heavily populated with people vacatiā¦Conneaut Lake is the largest natural lake in Pennsylvania by surface area. It is located in western Crawford County near a town with the same name. Its has a surface area of approximately 925 acres. The site of the lake is actually in adjacent Sadsbury Township and nearby Summit Township. During the summer season, it is heavily populated with people vacationing to the lake area, some from the area spending time in their houses on the lake, and many others from the surrounding area that like to spend the summer away from home, many of these people being residents of the Pittsburgh area. Other than the lake itself, the largest draw to the area has long been a popular resort known as Conneaut Lake Park, long known for its amusement park.