The City Hall Historic District includes buildings dating back to as far as 1823. Both Old City Hall (1830, 222 Merrimack Street) and New City Hall (1893, 375 Merrimack Street), can be found in the district along with many commercial, residential, religious, and institutional structures. It contains examples of all eras of the city's development and is the commercial and governmental center of the city. Examples of the Federal, Greek Revival, Gothic Revival, Italianate, Second Empire, High Victorian Gothic, Romanesque Revival, Richardsonian Romanesque, and Classical Revival styles can be found in the district among others. Listed on the National Register of Historic Places in 1975 with a boundary increase in 1988, the district includes 73 structures.
Lowell City Hall (1893), 375 Merrimack Street
Old City Hall (1830, 1896), 222 Merrimack Street
Bank Block (ca. 1826), 350 Merrimack Street
Moody-Francis-Whistler House (1825), 243 Worthen Street
Lowell Gas Light Company Building (1859), 22 Shattuck Street
Hovey House (1846) and J.C. Ayer Company (ca. 1892), Middle Street
Bon Marche Building (1874-1927), 159 Merrimack Street
Masonic Temple (1928), 79 Dutton Street
The district is also located within the boundaries of the National Register-listed Lowell National Historical Park & Preservation District (1978) as well as the Downtown Lowell Historic District (1983), a historic and architectural review district under the jurisdiction of the Lowell Historic Board.