Between 1811 and 1820. Regency period refers to the time when King George III was deemed unfit to rule and his son, the Prince Regent ruled as his proxy.

This time period fits snuggly in the Georgian period.

 

What happened? (from wiki with added links if you want to explore more)

1811  George Augustus Frederick, Prince of Wales^[5] began his nine-year tenure as regent and became known as The Prince Regent.  The Duke of Wellington held off the French at Fuentes d’Onoro and Albuhera in the Peninsular War.

1812 Spencer Perceval assassinated in the House of Commons.  Shipping and territory disputes started the War of 1812 between the United Kingdom and the United States. The British were victorious over French armies at the Battle of Salamanca. The waltz was introduced from Europe into England. Gas company (Gas Light and Coke Company) founded.

1813  Pride and Prejudice by Jane Austen was published. William Hedley’s Puffing Billy, an early steam locomotive, ran on smooth rails.

1814 Invasion of France by allies led to the Treaty of Paris, ended one of the Napoleonic Wars. Napoleon abdicated and was exiled to Elba. The Duke of Wellington was honoured at Burlington House in London.Last River Thames Frost Fair was held, which was the last time the river froze. Gas lighting introduced in London streets.

1815 Napoleon I of France defeated by the Seventh Coalition at the Battle of Waterloo. Napoleon was exiled to St. Helena. The English Corn Laws restricted corn imports.

1816  Income tax abolished.  Mary Shelley wrote Frankenstein.  The British returned Indonesia to the Dutch. Regent’s Canal, London, phase one of construction. Beau Brummell escaped his creditors by fleeing to France.

1817 Antonin Carême created a spectacular feast for the Prince Regent at the Royal Pavilion in Brighton. The death of Princess Charlotte from complications of childbirth changed obstetrical practices. Elgin Marbles shown at the British Museum. Captain Bligh died.

1818 Queen Charlotte died at Kew. Manchester cotton spinners went on strike. Piccadilly Circus constructed in London.

1819 Peterloo Massacre. Princess Alexandrina Victoria (future Queen Victoria) was christened in Kensington Palace. Ivanhoe by Walter Scott was published. Sir Stamford Raffles, a British administrator, founded Singapore. First steam-propelled vessel (the SS Savannah) crossed the Atlantic and arrived in Liverpool from Savannah, Georgia.

1820 Death of George III. Accession of The Prince Regent as George IV. The House of Lords passed a bill to grant George IV a divorce from Queen Caroline, but because of public pressure the bill was dropped. John Constable began work on The Hay Wain. Cato Street Conspiracy failed. Royal Astronomical Society founded. Venus de Milo discovered.

from: https://en.wikipedia.org/wiki/Regency_era