Question: Riverhead is a town that rests on the mouth of the Peconic River that is a river within Suffolk County in what state?

Context paragraphs:
Southold Town Police Department: The Southold Town Police Department, commonly referred to as STPD, is a professional police organization responsible for primary jurisdictional law enforcement for the town of Southold, New York.  Southold Town is located in Suffolk County.  The Southold Town Police Headquarters are located in the hamlet of Peconic, New York, with an address of 53095 Route 25, Peconic, NY 11958.  (631) 765-2600.

North Fork of Long Island AVA: The North Fork of Long Island AVA is an American Viticultural Area located in eastern Suffolk County, New York.  Authored by winemaker Richard Olsen-Harbich in 1985, it includes the entire North Fork of Long Island and the townships of Riverhead, Shelter Island, and Southold.  The North Fork of Long Island is home to 38 wineries and 3000 acre of planted vineyards.  The local climate is heavily influenced by the presence of Long Island Sound, Peconic Bay, and the Atlantic Ocean.  The maritime influences of these bodies of water help to moderate temperature fluctuations and extend the growing season up to a month longer than other regions in New York.  The most planted grape varieties in the region are Merlot, Chardonnay, and Cabernet Franc.  The hardiness zone is 7a.

South Jamesport, New York: South Jamesport is a hamlet in the town of Riverhead, Suffolk County, New York, United States.  The community is located on the north shore of the Great Peconic Bay.  South Jamesport has a post office with ZIP code 11970, which opened on February 2, 1893.

Suffolk County Sheriff's Office: The Suffolk County Sheriff's Office is the oldest law enforcement agency in Suffolk County, New York, having been established in 1683.  The Sheriff's Office currently employs over 1200 people, including 898 correction officers, 254 deputy sheriffs, and 130 civilian personnel.  Its Office and Business Operations are located at the Riverhead Correctional Facility, 100 Center Drive South in Riverhead (although it bears the Riverhead name, it is actually south of the Peconic River in Riverside in the Town of Southampton).

Riverhead Central School District: Riverhead Central School District is a public school district located in the eastern part of Suffolk County, New York, United States.  It primarily serves the Town of Riverhead, as well as 10 sqmi in the Town of Southampton and 3 sqmi in the Town of Brookhaven, and includes the census-designated places(CDPs) of Aquebogue, Baiting Hollow, Northville, Riverhead, and Riverside, and portions of Calverton, Flanders, Hampton Bays, Jamesport, Northampton, and Wading River.  The total district size is 81 sqmi .

Peconic County, New York: Peconic County (/pəˈkɒnɪk kaʊntiː/) is a proposed new county on Long Island in New York that would secede the five easternmost towns of Suffolk County: East Hampton, Riverhead, Shelter Island, Southampton and Southold, plus the Shinnecock Indian Reservation.

Riverhead (town), New York: Riverhead is a town within Suffolk County, New York, on the north shore of Long Island.  As of the 2010 census, the population was 33,506.  The town rests on the mouth of the Peconic River, from which it derives its name.  Since 1727, Riverhead has been the county seat of Suffolk County.  The smaller hamlet of Riverhead lies within it, and is the town's principal economic center.  The town is 166 miles (267 km) southwest of Boston via the Orient Point-New London Ferry, and is 76 miles (123 km) northeast of New York City.

Riverhead Town Police Department: The Riverhead Town Police Department, commonly referred to as RPD, is a professional police organization responsible for primary jurisdictional law enforcement for the Town of Riverhead, New York.  The Town of Riverhead is located in Suffolk County.  The Riverhead Town Police Headquarters are located in Riverhead, with an address of 210 Howell Avenue, Riverhead, NY 11901 (631) 727-4500.

Peconic River: The Peconic River is a river within Suffolk County on Long Island, New York in the United States.  The river is located in the eastern end of Long Island.  The Peconic River drains an area between the Harbor Hill and Ronkonkoma terminal moraines, and flows into Flanders Bay which in turn connects to Peconic Bay east of Riverhead.

Mattituck-Cutchogue Union Free School District: Mattituck-Cutchogue Union Free School District is a public school district located on the North Fork of Long Island, in Suffolk County, New York, United States.  It primarily serves the western part of the Town of Southold, as well as a small portion of the Town of Riverhead, and includes the census-designated places of Mattituck, Cutchogue and Laurel, and portions of Jamesport and Peconic.  To the east, the district is bordered by the Southold Union Free School District; and on the west, the Riverhead Central School District.

Supporting paragraphs: Riverhead (town), New York Peconic River
Answer: New York