Nashua is a city located in Hillsborough County, New Hampshire, along the Merrimack River. It is the second-largest city in the state with a population of 87, 882 as of 2019. Lowell is a city in Middlesex County, Massachusetts, located on the Merrimack River. It is the fourth-largest city in the state with a population of 106, 519 as of 2019. IRONCLAD is a term used to describe a type of warship that was heavily armored and designed to be resistant to enemy fire. The term was first used during the American Civil War, when the Union Navy built a number of IRONCLAD warships to combat the Confederate Navy. Ashland is a town in Middlesex County, Massachusetts, located on the Merrimack River. It has a population of 16, 593 as of 2019.