HMS Devonshire
County-class
General Characteristics
Displacement:	Around 10,000 tons standard (Around 8,400 to 8,600 tons in York class) / 13,300 tons to 13,700 tons (10,500 to 10,700 in York class)
Length:	630 ft (192 m), or 575 ft (175 m) York class
Beam:	68 ft (20.7 m) Kent class, or 58 ft (17.7 m) York class, or 66 ft (20.1 m) London and Norfolk classes
Draught:	16.4 ft (5.0 m)
Propulsion:	Parsons geared or Brown Curtis steam turbines, 4 shafts, 8 boilers, 80,000 shp (60 MN)
Speed:	32.5 knots (60.2 km/h)
Range:
Complement:	657 (628 York-class)
Armament:	Original configuration: 8 x 8 in (203 mm) guns (Eight x 8 in (203 mm) guns in York class) 4 x 4 in (102 mm) guns 8 x 2 pound (908 g) guns (Twelve in London class, sixteen in Norfolk class, two in York class) 8 x 21 in (533 mm) torpedo tubes (Six in York class)
Aircraft:	Removed in World War II

The County class were the first and last heavy cruisers of the Royal Navy, being built in four sub-classes, that became known as the Kent, London, Norfolk and York classes. The first three sub-classes were built to the constraints of the Washington Naval Treaty of 1922.

There were five ships of the Kent class built for the Royal Navy, and two ships, Australia and Canberra, were built for the Royal Australian Navy. All ships were commissioned in 1928. The Kents were heavily armed, having eight 8-inch (203 mm) guns in four twin turrets. Their secondary armament consisted of four 4-inch (102 mm) single guns and also had eight 2 pound (0.9 kg) guns for anti-air warfare.

The ships were large, at 630 feet (192 m), though they had no side armour when built. The British Kents were reconstructed in the 1930s, with its armour being increased and its 2-pound (0.9 kg) guns being increased to sixteen in two octuple guns. Their eight 21-inch (533 mm) torpedo tubes were also removed, though Kent retained them. Their secondary armament was increased with the addition of two twin 4-inch (102 mm) guns. One twin 8-inch (203 mm) turret was removed in 1941. Their aircraft hangar, which had been added before the war was removed during World War II.

The second sub-class, the London class, also known as the Devonshire class, consisted of four ships and were modified from the Kents. The Londons were virtually identical to the Kents, but differed in that their superstructure was altered slightly and internal bulges were added to give protection from torpedoes and the increase of their 2-pound (0.9 kg) guns to twelve. In the 1930s, the Londons underwent similar alterations that the Kents did, having their eight 21-in (533 mm) torpedo tubes removed, and one twin 8-inch (203 mm) turret removed, though London retained it. One ship, Shropshire, was transferred to the Royal Australian Navy in 1943 to replace Canberra. London was completely rebuilt just before, and during, World War II, giving her the appearance of a Crown Colony-class cruiser.

The third sub-class, the Norfolk class, also known as the Dorsetshire class consisted of two ships and were again similar to its predecessors, having only very slight differences, such as having the new lighter MkII turret for their 8-inch (203 mm) guns and small differences to the superstructure and an increased in the amount of 2-pound (0.9 kg) guns, to sixteen. Like the previous two sub-classes, the Norfolks underwent a number of alterations in the 1930s, having their four 4-inch (102 mm) single guns replaced by four twin 4-inch (102 mm) turrets. Their 2-pound (0.9 kg) guns were increased twenty-four during World War II.

The York class consisted of two ships (five were cancelled), and differed slightly from the previous three sub-classes. They had fewer 8-inch (203 mm) guns, having six in twin turrets and having just two 2-pound (0.9 kg) guns and had increased armour. Their length was considerably smaller, at 575 ft (175 m) and they had two funnels rather than the three in the previous sub-classes. The Yorks underwent modifications similar to the three previous sub-classes during the 1930s, having their four single 4-in (102 mm) guns replaced with four twin 4-inch (102 mm) turrets. Their six 21-inch (533 mm) torpedo tubes were also removed. During World War II, their 2-pounder guns were given a substantial increase to twenty-four. The Yorks had the distinction of being the last warships of the RN to be armed with 8-inch (203 mm) guns.

The County class saw much service during the Second World War including the battle of the River Plate, where Exeter performed with distinction in the battle against the German pocket battleship Admiral Graf Spee, suffering heavy damage in the process. The class saw service in nearly every other theatre of the war. The County class suffered a number of losses, with Canberra, Cornwall, Dorsetshire, Exeter and York all being lost. The survivors were all decommissioned by the 1950s.