Question: What county in Massachusetts has a state forest and an island that the Rowley River runs by?
Context: Mattatuck State Forest is a Connecticut state forest spread over twenty parcels in the towns of Waterbury, Plymouth, Thomaston, Watertown, Litchfield, and Harwinton.  The Naugatuck River runs through a portion of the forest.  The largest section of the forest is located about 1 mi north of Waterbury.  The Leatherman's Cave, named after the vagabond Leatherman of the late 19th century, is located in Thomaston on the Mattatuck Trail, just north of the junction with the Jericho Trail. The Roger Island River is a small tidal estuary between Ipswich and Rowley, Massachusetts.  It is a southern branch of the larger Rowley River passing around Roger Island. Natchaug State Forest is a Connecticut state forest located in six towns including Ashford, Chaplin, and Eastford.  The Natchaug River runs from north to south along (and in a few cases through) the western border of the main forest parcel.  James L. Goodwin State Forest abuts Natchaug State Forest to the south.  One of the forest units abuts Mashamoquet Brook State Park in Pomfret. The Rowley River is a small river between Ipswich and Rowley, Massachusetts. Holy Island is a marshy island located off the northeast coast of Massachusetts, north of Cape Ann.  The island is situated immediately west of Plum Island and is part of the Town of Ipswich in Essex County.  The Rowley River runs by the island, which is the northernmost of four marshy islands. Ipswich is a coastal town in Essex County, Massachusetts, United States.  The population was 13,175 at the 2010 census.  Home to Willowdale State Forest and Sandy Point State Reservation, Ipswich includes the southern part of Plum Island.  A residential community with a vibrant tourism industry, the town is famous for its clams, celebrated annually at the Ipswich Chowderfest, and for Crane Beach, a barrier beach near the Crane estate.  Ipswich was incorporated as a town in 1634. The Pine Island State Forest is a Minnesota state forest located primarily in Koochiching County, although there are portions that extend into Beltrami, Lake of the Woods, and Itasca counties.  The forest borders the Koochiching State Forest to the east, the Red Lake State Forest to the west, and Big Fork State Forest and Chippewa National Forest to the south.  At an area of 878040 acre , it is the largest state forest in Minnesota. The Koochiching State Forest is a state forest located near International Falls in Itasca, Koochiching, and Saint Louis counties, Minnesota.  The forest borders the Pine Island State Forest to the west, the Big Fork State Forest and George Washington State Forest to the south, the Nett Lake Indian Reservation and the Kabetogama State Forest to the east.  A leg of the forest touches Rainy Lake to the north, which forms part of the international border with Ontario.  Of the 565500 acre , 344300 acre are managed by the Minnesota Department of Natural Resources, making it one of the largest forests in the Minnesota state system. Pike State Forest is a 4444 acre state forest in Pike County, Indiana.  The nearest city to the forest is Winslow.  The Patoka River runs through the forest, which has a varied topography consisting of both hills and lowlands near the river.  The land comprising the forest was acquired over a period ranging from the 1930s to the 1950s.  The buildings and facilities in the forest were mainly constructed by the Works Progress Administration using wood from the area.  Pike is administered by the Indiana Department of Natural Resources; since 1997, it has been under the administration of nearby Ferdinand State Forest. Georgetown-Rowley State Forest is a 1112 acre Massachusetts state forest located primarily in the towns of Georgetown and Rowley with a small spillage into the town of Boxford.  The forest straddles Interstate 95 and abuts Willowdale State Forest at its southeastern edge.  The forest is managed by the Massachusetts Department of Conservation and Recreation.
Answer: Essex County