The primary settlement in town, where 7,336 people resided at the 2010 census, is defined as the Hudson census-designated place (CDP) and is located at the junctions of New Hampshire routes 102, 111 and 3A, directly across the Merrimack River from the city of Nashua.
Hudson began as part of the Dunstable Land Grant that encompassed the current city of Nashua, New Hampshire, and the towns of Dunstable and Pepperell, Massachusetts, as well as parts of other nearby towns on both sides of the border. In 1732, all of Dunstable east of the Merrimack River became the town of Nottingham, Massachusetts. Nine years later, the northern boundary of Massachusetts was finally officially established, and the New Hampshire portion of Nottingham became Nottingham West, to avoid confusion with Nottingham, New Hampshire to the northeast.
In 1830, after the better part of a century, the name was changed to "Hudson" to avoid confusion with the older town of Nottingham. The name apparently comes from an early belief that the Merrimack River had once been thought to be a tributary of the Hudson River, or that the area had once been explored by Henry Hudson; both proved to be entirely apocryphal stories, but the name of the town remains today.
A prominent family in Hudson history was the Alfred and Virginia Hills family, who owned a large tract of land north of Hudson Village. Dr. Hills' ancestors were original settlers of Hudson. The Hills House on Derry Road (now listed on the National Register of Historic Places) is their original family's vacation home and current location of the Town Historical Society. The grounds host the annual "Old Home Days" fair every year as well as "Harvest Fest" and the "Bronco Belly Bustin' Chili Fiesta", an Alvirne High School Friends of Music fundraiser. Hills Memorial Library (also listed on the National Register) is one of the oldest public lending libraries in the state, and occupies a stone and mortar building on Library Street. Alvirne High School and the Alvirne Chapel, located on family land across Derry Road from the Hills House, were donated to the town. (Alvirne is a contraction of Alfred and Virginia). A strange rumor that The Hills' only son had died during a football game circled for many years, but Dr. and Mrs. Hills only had two daughter who did not survive infancy, so this was a made up story. Out of respect, Alvirne High went many decades without a football team, despite being one of the largest high schools in the state. It was assumed that such a stipulation had been put as a condition of the high school's charter. When it was learned that no such condition had ever been recorded, financial pressures encouraged the formation of a football team. In fall of 1994, Alvirne High School fielded its first JV football team, with varsity play beginning in 1996. Alvirne High is home to one of the largest agricultural-vocational programs in the area, the Wilbur H. Palmer Agricultural and Vocational School. This school features several student-run businesses including a bank, restaurant, store, day care, dairy farm, and forestry program.