Henry William Paget, 1st Marquess of Anglesey (17 May 1768 - 29 April 1854) was a British military leader and politician, now chiefly remembered for an incident during the Battle of Waterloo.

He was the eldest son of Henry Paget, 1st Earl of Uxbridge (d. 1812), and was educated at Westminster School and Christ Church College, Oxford, afterwards entering parliament in 1790 as member for Caernarvon, for which he sat for six years. At the outbreak of the French Revolutionary wars Lord Paget (as he was then styled), who had already served in the militia, raised on his father's estate the regiment of Staffordshire volunteers, in which he was given the temporary rank of lieutenant-colonel (1793). The corps soon became part of the regular army as the 50th Foot, and it took part, under Lord Paget's command, in the Flanders campaign of 1794. In spite of his youth he held a brigade command for a time, and gained also, during the campaign, his first experience of the cavalry arm, with which he was thenceforward associated. His substantive commission as lieutenant-colonel of the 16th Light Dragoons bore the date of the 15 June 1795, and in 1796 he was made a colonel in the army. In 1795 he married Lady Caroline Elizabeth Villiers, daughter of the Earl of Jersey. In April 1797 Lord Paget became a lieutenant-colonel in the 7th Light Dragoons, and colonel of the regirment in 1801. From the beginning he concentrated on the improvement of discipline and the perfection of a new system of cavalry evolutions. In the short campaign of 1799 in Holland, Paget commanded the cavalry brigade, and in spite of the unsuitable character of the ground, he made, on several occasions, brilliant and successful charges. After the return of the expedition, he devoted himself zealously to his regiment, which under his command became one of the best corps in the service. In 1802 he was promoted major-general, and six years later lieutenant-general. In command of the cavalry of Sir John Moore's army during the Corunna campaign, Lord Paget won the greatest distinction. At Sahagun, Mayorga and Benavente, the British cavalry behaved so well under his leadership that Moore wrote:— " It is impossible for me to say too much in its praise. . . . Our cavalry is very superior in quality to any the French have, and the right spirit has been infused into them by the example and instruction of their . . . leaders . . . ." At Benavente one of Napoleon's best cavalry leaders, General Lefebvre Desnoettes, was taken prisoner. Corunna was Paget's last service in the Peninsular Wars. His liaison with the wife of Henry Wellesley, afterwards Lord Cowley, made it impossible at that time for him to serve with Wellington, whose cavalry, on many occasions during the succeeding campaigns, felt the want of the true cavalry leader to direct them. His only war service from 1809 to 1815 was in the disastrous Walcheren expedition (1809) in which he commanded a division. During these years he occupied himself with his parliamentary duties as member for Milborne Port, which he represented almost continuously up to his father's death in May of 1812, when he took his seat in the House of Lords as the 2nd Earl of Uxbridge. In 1810 he was divorced and married Mrs Wellesley, who had about the same time been divorced from her husband. The former Lady Paget was soon afterwards married to the Duke of Argyll. In 1815 Lord Uxbridge received command of the British cavalry in Flanders. At a moment of danger such as that of Napoleon's return from Elba, the services of the best cavalry general in the British army could not be neglected. Wellington placed the greatest confidence in him, and on the eve of Waterloo extended his command so as to include the whole of the allied cavalry and horse artillery. He covered the retirement of the allies from Quatre Bras to Waterloo on 17 June, and on 18 June gained the crowning distinction of his military career in leading the great cavalry charge of the British centre, which checked and in part routed D'Erlon's corps d'armee. Freely exposing his own life throughout, the earl received, by one of the last cannon shots fired, a severe wound in the leg, necessitating amputation.

This is the event which caused Paget's name to go down in history. According to anecdote, he was close to Wellington when his leg was hit, and exclaimed, "By God, sir, I've lost my leg!" -- to which Wellington replied, "By God, sir, so you have!" He was afterwards nicknamed "One Leg". Five days later the Prince Regent created him Marquess of Anglesey in recognition of his brilliant services, which were regarded universally as second only to those of the duke himself. He was made a G.C.B and he was also decorated by many of the allied sovereigns.

In 1818 the marquess was made a Knight of the Garter, in 1819 he became full general, and at the coronation of George IV he acted as Lord High Steward of England. His support of the proceedings against Queen Caroline made him for a time unpopular, and when he was on one occasion beset by a crowd, who compelled him to shout "The Queen," he added the wish, "May all your wives be like her." At the close of April 1827 he became a member of the Canning administration, taking the post of Master-General of the Ordnance, previously held by Wellington. He was at the same time sworn a member of the Privy Council. Under the Wellington administration he accepted the appointment of Lord Lieutenant of Ireland (March 1828), and in the discharge of his important duties he greatly endeared himself to the Irish people. The spirit in which he acted and the aims which he steadily set before himself contributed to the allaying of party animosities, to the promotion of a willing submission to the laws, to the prosperity of trade and to the extension and improvement of education. On the great question of the time his views were opposed to those of the government. He saw clearly that the time was come when the relief of the Catholics from the penal legislation of the past was an indispensable measure, and in December 1828 he addressed a letter to the Roman Catholic primate of Ireland distinctly announcing his view. This led to his recall by the government, a step sincerely lamented by the Irish. He pleaded for Catholic emancipation in parliament, and on the formation of Earl Grey's administration in November 1830, he again became lord-lieutenant of Ireland. The times were changed; the act of emancipation had been passed, and the task of viceroy in his second tenure of office was to resist the agitation for repeal of the union carried on by O'Connell. He felt it his duty now to demand Coercion Acts for the security of the public peace; his popularity was diminished, differences appeared in the cabinet on the difficult subject, and in July 1833 the ministry resigned. His viceregency also saw the establishment of the Irish Board of Education. For thirteen years after his retirement he remained out of office, and took little part in the affairs of government. He joined Lord John Russell's administration in July 1846 as master-general of the ordnance, finally retiring with his chief in March 1852. His promotion in the army was completed by his advancement to the rank of field-marshal in 1846. Four years before, he exchanged his colonelcy of the 7th Light Dragoons which he had held over forty years, for that of the Royal Horse Guards.

The marquess had a large family by his two wives, two sons and six daughters by the first and six sons and four daughters by the second.

{| border="2" align="center" |- |width="30%" align="center"|Preceded by:
New Creation |width="40%" align="center"|Marquess of Anglesey |width="30%" align="center" rowspan="2"|Followed by:
Henry Paget |- |width="30%" align="center"|Preceded by:
Henry Paget |width="40%" align="center"|Earl of Uxbridge |}