C. Willis Damon (1850-1916) was an American architect from Haverhill, Massachusetts.

Damon was born in Pawtucket, Rhode Island in 1850. He was the son of Calvin Damon, a Universalist minister. Around 1856 the family moved to Haverhill.^[1] Damon graduated from the architectural program at the Massachusetts Institute of Technology, then only a few years old.^[2] Beginning in 1873 he was practicing architecture in Haverhill. He was the city's first college-trained architect. In 1874 or 75 he took his brother, Charles P. Damon (d.1919), as a partner.^[3] The firm, Damon Brothers, lasted until 1915, at which point Damon appears to have retired. His brother continued the practice for a few more years, doing only minor work.

• Winnekenni Hall (James R. Nichols Estate), 347 Kenoza Ave., Haverhill, MA (1873–75)^[4]
• James A. Hale House, 65 Cedar St., Haverhill, MA (c.1875)^[5]
• William B. Thom House, 284 Washington St., Haverhill, MA (1877)^[6]
• Jane P. Chase House, 148 Main St., Haverhill, MA (1878–79)^[7]
• William J. Edwards House, 52 Park St., Haverhill, MA (c.1878)^[8]
• Leonard V. Spaulding House, 17 Beacon St., Haverhill, MA (1878)^[9]
• First Universalist Church, 151 Main St., Kingston, NH (1879)^[2]
• Freewill Baptist Church (former), 7 Church St., Deerfield, NH (1881)^[10]
• Gatehouse (Remodeling), Grey Court (Charles H. Tenney estate), Methuen, MA (1883)
• Holley Hall, 1 South St., Bristol, VT (1884)^[11]
• Herbert O. Delano House, 23 W. Main St., Merrimac, MA (1885)^[12]
• Joel Butler House, 75 Auburn St., Haverhill, MA (1886) - Altered.^[13]
• Winthrop N. Dow House, 75 Front St., Exeter, NH (1887)^[14]
• Addison B. Jaques Duplex, 24-26 Cedar St., Haverhill, MA (1887)^[15]
• Daggett Building, 91 Merrimack St., Haverhill, MA (1887) - Demolished.^[16]
• Grafton County Courthouse, 35 S. Court St., Woodsville, NH (1889–91)^[16]
• Grafton County Courthouse, 6 Post Office Sq., Plymouth, NH (1890–91)^[17]
• Opera Block, 65 Central St., Woodsville, NH (1890)^[16]
• C. Willis Damon House, 289 Mill St., Haverhill, MA (1891) - The home of the architect.^[18]
• Rockingham County Courthouse, State St. near Penhallow, Portsmouth, NH (1891–93) - Demolished.^[16]
• Blanchard's Block, 1-3 S. Main St., Concord, NH (1894)^[16]
• Peabody School, 170 Salem St., Bradford, MA (1895)
• Arthur B. Sumner House, 295 Mill St., Haverhill, MA (1898)^[19]
• Walnut Square School, 645 Main St., Haverhill, MA (1899)^[20]
• Wilman Block, 105 Main St., Amesbury, MA (1899)^[21]
• Monument Street School, 170 Monument St., Haverhill, MA (1900) - Demolished.^[22]
• St. Gregory's R. C. School, 108 Harrison St., Haverhill, MA (1901)^[23]
• Haverhill Building Association Building, 16-38 Walnut St., Haverhill, MA (1906–08) - Also known as the Board of Trade Building.^[24]
• R. L. Wood School, 255 S. Spring St., Haverhill, MA (1906)^[25]
• Merrimack Associates Building, 25 Locust Ave., Haverhill, MA (1913)^[26]
• Essex Associates Building, 109 Essex St., Haverhill, MA (1915)^[27]
• William A. Knipe School, 97 Oxford Ave., Haverhill, MA (1915)^[28]

Damon was selected as the architect of the 1909 High School (now City Hall), but was ultimately made supervising architect for Kilham & Hopkins of Boston.^[29]