The Hill Memorial was constructed in 1916 by Newton contractor Thomas Farrel in renaissance revival style according to the design of Henry T. Stephens, a Paterson architect. It was built for the society's use by donations from Joshua Hill, a native of Sussex County and was dedicated on Founder's Day, June 8, 1917. The building was named in memory of Joshua's parents, Luther and Abigail (Dildine) Hill, and his uncle, Joseph Price Hill. The building is faced with two shades of tapestry brick furnished by the N.H. Sloan kilns of Pennsylvania. The main entrance is ornamented with a portico and door casings manufactured by the Brick Terra Cotta & Tile Company of Corning, New York. The main architectural feature of the entry hall is the grand staircase of quartered oak.

The Sussex County Room

Located on the ground floor, this room features a large stone fireplace built by George Sharp in 1922, incorporating stones of local geological and historic significance.

A framed copy of Carlos Allen's Map of Sussex County (1869) hangs above the oak roll-top desk of Judge Henry T. Kays.

Portraits of Luther and Abigail (Dildine) Hill, and of past society presidents, William Woodward, hardware merchant, and Jacob Bunnell, editor of the New Jersey Herald, are also on display.

Victorian display cases upstairs in the Assembly Room were custom made for jeweler H.D. Couse, and donated by his successor, John Coats, Sr., when Coats Jewelry Store moved in 1950 from the Cochran House store to 103 Spring Street. Here are the Society's collections of local samplers, coverlets, quilts, agricultural implements, early baskets, household utensils, and Civil War memorabilia. One of Society's most fascinating artifacts is the partial skeleton of a Mastodon discovered between 1962-65 during dredging of a bog at Camp Auxilium, Hampton Township

Stained glass transoms were salvaged from Klingener's Candy Store in Newton. Also on display are pig iron from the Andover Furnace (1759-1795), a toll sign from the Morris Turnpike (1901), and items from Newton's famous Cochran House (1843-1961) including a guest register and a chair from the log cabin dining room, and monogrammed china and silverware.