The Northamptons saw much action in World War II. Three (Northampton, Chicago, and Houston) were lost during the war. The other three were decommissioned soon after the end of the war, and scrapped in 1959–1961.
The design of the ships was heavily influenced by the Washington Naval Treaty, which limited cruisers to a maximum of 10,000 tons displacement and a maximum main battery caliber of 8inches. The Northamptons were a reaction to the weight and cost of the immediately preceding, differing in several ways. The Pensacolas mounted a main battery of 10 8inches guns in four turrets, a twin and superfiring triple fore and aft. In contrast, the Northamptons mounted 9 8inches guns in three triple turrets, two forward and one aft, the layout followed in all subsequent U.S. heavy cruisers.
Although armor was increased, the Northamptons turned out to be lighter than the Pensacolas, and nearly 1,000 tons below the treaty limitations. Freeboard was increased in the Northamptons by adopting a high forecastle, which was extended aft in the last three for use as flagships. These ships were also the first U.S. ships to adopt a hangar for aircraft, and bunks instead of hammocks. Their lighter-than-expected weight caused them to roll excessively, which necessitated the fitting of deep bilge keels. The immediately-following was essentially a modified Northampton.
| Ship name | Builder | Laid down | Launched | Commissioned | Decommissioned | Fate | |
|---|---|---|---|---|---|---|---|
| CA-26 | Bethlehem Steel Corporation, Fore River Shipyard, Quincy, Massachusetts | 12 April 1928 | 5 September 1929 | 17 May 1930 | Sunk in the Battle of Tassafaronga, 30 November 1942 | ||
| CA-27 | New York Shipbuilding Corporation, Camden, New Jersey | 6 March 1928 | 3 July 1929 | 24 June 1930 | 10 June 1946 | Struck 1 March 1959; Sold for scrap, 11 August 1959 | |
| CA-28 | Puget Sound Navy Yard | 4 July 1928 | 1 September 1930 | 15 January 1931 | 17 June 1946 | Struck 1 March 1959; Sold for scrap, 14 September 1959 | |
| CA-29 | Mare Island Naval Shipyard | 10 September 1928 | 10 April 1930 | 9 March 1931 | Sunk during the Battle of Rennell Island, 30 January 1943 | ||
| CA-30 | Newport News Shipbuilding and Dry Dock Company | 1 May 1928 | 7 September 1929 | 17 June 1930 | Sunk in the Battle of Sunda Strait, 1 March 1942 | ||
| CA-31 | 2 July 1928 | 1 February 1930 | 30 January 1931 | 16 July 1946 | Struck 1 March 1959; Sold for scrap, 9 November 1959 |