Question: The Ashland Gristmill and Dam is locate in what county?
Context: The Ashland Mill Bridge was a lenticular pony truss bridge over the Pachaug River in Griswold, Connecticut that was built in 1886 by the Berlin Iron Bridge Company.  It was built following the Ashland dam break of February 1886 which washed away the previous bridges.  The bridge served the millyard of the Ashland Cotton Company, in the Jewett City section of Griswold.  The bridge was 65 ft long and crossed a millrace on a skew angle.  The Ashland Mill was damaged by arson in March 1994 and subsequently torn down, but the bridge itself remained.  By 1999, the town deemed the bridge unsafe and closed it, and by February 1999, the bridge was moved to a vacant parking lot and was replaced with a new bridge.  The bridge was added to the state of Connecticut historic register and it was later added to the National Register of Historic Places in April 1999.  It was removed from the National Register in February 2016. The Ashland Gristmill and Dam are a historic former industrial facility in the heart of Ashland, New Hampshire.  The dam, originally a wooden construction, is a concrete structured located on the Squam River, where Main Street (New Hampshire Route 132) crosses the river.  It is 180' long, 14' high, and has a 50' spillway.  The mill building located at the northeast corner of Main Street and Daniel Webster Highway was built in 1903 on the site of a gristmill that was destroyed by fire.  It has a massive timber frame, whose most prominent feature is a central tower from which wings balloon out.  Its basement still houses the turbine and controlling hardware, although these are no longer operational. Pleasant Hill Lake is an 783-acre man made lake located near Perrysville and between Ashland and Richland counties in Ohio.  Completed in 1936, Pleasant Hill Dam was built on the Clear Fork of the Mohican River.  The dam which forms the lake is a 113 ft tall earth-fill dam.  It is located in Ashland but the lake extends into Richland.  The lake, constructed by the United States Army Corps of Engineers, was built for the purpose of flood control. The Cedarburg Mill is a gristmill in Cedarburg, Wisconsin that is listed on the U.S. National Register of Historic Places.  It was built in 1855 by Frederick Hilgen and William Schroeder to replace the wooden gristmill they had built in 1844.  The architect and builder was Burchard Weber.  At five stories high, Cedarburg Mill was the tallest building in Cedarburg when it was built and at the time cost $22,000.  The mill is built on Cedar Creek.  Hilgen and Schroeder built a dam on the creek near the mill, and put a water wheel near the dam to power the mill.  The mill could produce 120 barrels of flour each day, which was sold in a shop owned by Hilgen and Schroeder.  Because the Cedarburg Mill prospered, four other mills were built along Cedar Creek.  The mill building is now owned by Landmark Supply Co. Ashland is a town in Grafton County, New Hampshire, United States.  The population was 2,076 at the 2010 census.  Located near the geographical center of the state, Ashland is home to Scribner-Fellows State Forest. Ashland is a home rule-class city in Boyd County, Kentucky, in the United States.  Ashland, the largest city in Boyd County, is located upon the southern bank of the Ohio River.  The population was 21,684 at the 2010 census.  Ashland is a part of the Huntington-Ashland metropolitan area; with a population of 363,000.  Ashland is the second-largest city within the MSA, after Huntington, West Virginia.  Ashland serves as an important economic and medical center for northeast Kentucky and is part of the fifth-largest metropolitan area in Kentucky. The Ashland Dam and Spillway is a historic site at the north end of Ashland Reservoir in Ashland State Park in Ashland, Massachusetts.  Ashland Reservoir was constructed in 1885, impounding a portion of Cold Spring Brook, a tributary of the Sudbury River.  The dam and spillway were built as part of Boston's second major water works effort, which impounded large portions of the upper Sudbury River.  They were listed on the National Register of Historic Places in 1990. Brake is an unincorporated community on the South Fork South Branch Potomac River in Hardy County, West Virginia, United States.  The community is named for the family of early landowner Johann Jacob Brake ("Brechtel" in German) who emigrated from southern Germany in the early 18th century.  The town once included a sawmill, gristmill, distillery, blacksmith shop, and post office.  The original log house used as a post office in the early- to mid-19th century still stands.  The Brake Cemetery harbors the remains of Brakes, Simons, Sees, and probably others whose stones have been lost.  Brake Falls on Dumpling Run once provided power for the sawmill and gristmill. Graves Mill, also known as Jones Mill and Beech Grove Mill, is a historic grist mill complex located near Wolftown, Madison County, Virginia.  The complex includes a three-story, heavy timber frame gristmill; a two-story, log, frame, and weatherboard miller’s house; and a one-story heavy timber frame barn.  The gristmill was built about 1798, probably on the foundation of an earlier gristmill built about 1745.  It was owned and operated by members of the Thomas Graves family for more than a century. Audra State Park is a West Virginia state park located on 355 acre in southwestern Barbour County.  It was established around the remnants of an early 19th-century gristmill and the tiny community of Audra.  A gristmill spillway is still visible in the river.
Answer: Grafton County