A light cruiser is a warship that is not so large and powerful as a regular (or heavy) cruiser, but still larger than ships like destroyers. They were first built in Britain with Mercury in 1879, and gradually became faster and more powerful, with greater numbers of uniform size main guns. Germany took the lead in light cruisers in the 1890s, building a class of fast cruisers copied by other nations.

By World War I, British light cruisers often had either two 6 inch (200 mm) and perhaps eight 4 inch (100 mm) guns, or a uniform armament of 6 inch (200 mm) guns, while German cruisers progressed during the war from 4.1 inch (100 mm) to 5.9 inch (150 mm) guns.

In the Washington Naval Arms Limitation Treaty of 1920, light cruisers were defined as cruisers having guns of 6.1 inch (150 mm) or smaller, with heavy cruisers defined as cruisers having guns of up to 8 inch (200 mm).

In the World War II era, light cruisers had guns ranging from 5.00 inch (127 mm) to 6.1 inch (150 mm), the most common size being 6in (152mm), while heavy cruisers usually had a battery of 8 inch (200 mm) guns. This was a significant difference in destructive power, since 8 inch (200 mm) shells were over twice the weight of 6 inch (200 mm) shells. Light cruisers were nevertheless useful for fire-support and as fleet escorts, and heavily used.

Four light cruisers are still in existence: HMS Belfast (1938) in London, HMS Caroline in Belfast External site (scroll down) (http://www.battleships-cruisers.co.uk/caroline_class.htm) External site (http://www.royal-navy.mod.uk/static/pages/2474.html) Little Rock (Buffalo), and Colbert (Bordeaux). Similar ships include the protected cruisers Aurora (St Petersburg), part of Puglia (Italy) and Olympia.

Light cruisers of the United States Navy

In the United States Navy, light cruisers have the hull classification symbol CL. Both heavy cruisers and light cruisers were classified under CL after 1931, hence there are some missing hull numbers.

United States Navy
Hull Number1	Class	Years in service
CL-1 to CL-3	Chester	1908–1930
Cl-4 to CL-13	Omaha	1923–1949
CL-14	Not Assigned, intended for USS Chicago
CL-15	USS Olympia	1895–1957
CL-16 to CL-21	Denver	1903–1933
CL-22	USS New Orleans	1898–1930
CL-23	USS Albany	1900–1930
CL-40 to CL-43, CL-46 to CL-48	Brooklyn	1937–1992
CL-49 and CL-50	St. Louis	1930–1951
CL-51 to CL-54	Atlanta	1941–1959
CL-55 to CL-67, CL-76 to CL-94, CL-99 to CL-105	Cleveland Note: nine Cleveland-class cruisers were converted to Independence-class aircraft carriers	1942–1971
CL-95 to CL-98	Oakland	1943–1966
CL-106 to CL-118	Fargo	1945–1970
CL-119 to CL-121	Juneau	1946–1966
CL-144 to CL-147	Worcester	1948–1970
CL-154 to CL-159	abortive 1945 antiaircraft cruiser project	none built
CLGN-160 (to CGN-160 and then to CGN-9)	USS Long Beach	1961–1995

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