St George’s Day is England’s national day – St George was named as England’s principal patron saint in 1416.
St George’s Day is listed as a flag flying day (for England only) by UK government guidance.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
The Union Flag is specified.
Oliver Cromwell (1599–1658) was an English statesman, politician and soldier.
He was MP for his native Huntingdon (1628-9).
Staffordshire Day commemorates the foundation date of Josiah Wedgwood and Sons (1759).
The date was selected by public vote from a list that includes: 5 July – discovery of the Staffordshire Hoard (2009); 6 September – the future King Charles II hid in an oak tree in South Staffordshire (1651); 18 September – Doctor Samuel Johnson born in Lichfield (1709); 27 September – James Brindley, renowned engineer and resident of Leek, died (1772)
Somerset Day was selected by public vote from a shortlist that includes: 19 May – Feast of St Dunstan; 6 July – Battle of Sedgemoor.
The battle of Albuera (1811) took place during the Peninsular War, when Anglo-Portuguese forces defeated the French.
The 57th (West Middlesex) Foot suffered very heavy casualties during the battle and later celebrated the anniversary as a regimental day.
St Aldhelm (639–709) was Abbot of Malmesbury and Bishop of Sherborne.
Wiltshire Day takes place annually on 5 June.
It commemorates the first raising of the Wiltshire Flag at County Hall, Trowbridge (2007).
Sussex Day takes place annually on 16 June, the feast of St Richard of Chichester (1197–1253), the patron saint of Sussex.
Also known as Richard de Wych, the saint was bishop of Chichester.