Between 1703 and 1711 William Richardson sat as MP for Hillsborough under the patronage of the Hill family. This followed a campaign by the government of the day to prevent him winning the Armagh seat.

William Richardson died in 1727, having once more been elected as member for Armagh. He was succeeded in Richhill by his brother John (1653-1744).

A shortage of small change in Ireland led to Samuel Mackie of Richhill, a horologist, issuing his own 3d pieces.

The Famine of 1740-41 (bliain an áir) is estimated to have led to the deaths of 300,000-480,000 people. There are no records extant that refer specifically to Richhill during this period, but it is highly unlikely that the village escaped unscathed.

John Richardson left few records and was not an MP. He married Anne Beckett, daughter of a lawyer, and had four children. One of these, Mary, married Archibald Acheson of Markethill and the couple had ten children. Thereafter the two families were closely linked. Archibald later became the 1st Viscount Gosford.

Isabella Mussenden was the daughter of a wealthy Belfast merchant. Her dowry of £5,000 was a welcome relief to the heavily indebted Richardson.

William Richardson was educated at Drogheda Grammar School and Christ Church, Oxford where he studied law. By 1775 he had moved to Dublin and was embarking on a career in politics.

The market house provided a venue for weavers and buyers to meet. In 1837, following the decline in the linen trade, the market house was converted into St Mathew's Church.

Isabella Richardson died from a "hectic fever" in December 1753, having a five-year-old son, William.

The Richhill Independent Troop of Dragoons was raised in 1756. It rode to Belfast under Colonel William Richardson and Lt Roe in order to help defend Carrickfergus from the French.

William Richardson MP died in Dublin leaving his young son in the care of his uncles; Colonel Henry Richardson and Sir Archibald Acheson. The two guardians quarrelled over the management of the Richhill estate, especially when Henry let out the Castle to the Archbishop of Armagh.

Some 254 drapers from Richhill, Newry, Armagh and elsewhere appended their name to ta petition, which asserted their intention to continue attending the market at Richhill despite Mr. Obins securing a patent for a brown linen market in Portadown.

Baratariana was a satire on the administration of Lord Townsend, the English Lord Lieutenant sent to Dublin to curb the power of local magnates and improve the government of Ireland. Baratariana was written by the Patriots Henry Grattan, Henry Flood and Hercules Langrishe. Dorothea Monroe and her family are included in the cast list. This work was the origin of the story that Lord Townsend had pretended to court Dorothea in order to gain the support of the Earl of Ely , her uncle. Recent research has shown this to have been highly unlikely.

The working classes in Richhill and other parts of Co Armagh rose up against the clergy and local landowners following the imposition of unduly harsh charges and taxes. Magistrates and the gentry were intimidated but the disturbances were largely peaceful. An official in Dublin Castle summarised the events thus:

“In the beginning, any justice with two constables could have nipp’d it in the bud, but Brownlow, who was most concerned in it, being absent in England, it was no other person’s concern and nobody else’s business to step forth in support of an unpopular measure [...] Every barony is to be charged with the repair of its own roads. Mr. Brownlow’s barony in the county of Armagh is a small one. He got [...] £150 for making roads for the benefit of his own estate, which sum when it came to be levied on the inhabitants of the barony amounted to one shilling, some say eighteen pence an acre. The people refused to pay it and rose in a body to oppose it and they at first only swore the tenants in that particular barony not to pass the cess. After finding themselves strong they thought that whilst they were in the field they might as well redress some other grievances and thereupon they swore people not to pay the small dues to the clergy, etc. etc. They seem to direct their resentment against tithe gatherers, principally, and such justices of the peace who have issued any warrants against such people who have refused payment of the small dues. By all accounts they consist of people of all religions but are mainly Presbyterians. Undoubtedly the small dues have been exacted with rigour and gentlemen have gotten great sums [...] for jobs for themselves and I have often heard it said that in other respects the common people are treated with vast rigour and severity by the gentlemen. I never heard that they refused to pay hearth money or inland excise.”

St Patrick’s Roman Catholic Church at Stonebridge in Richhill is reported by the surveyor Thomas McIlroy in 1837 to have been built in 1771.

Others believe that it was built in 1775 at the instigation of Dorothea Monroe who, out for a drive with her new husband William Richardson, saw a group of Catholics celebrating Mass under a hedge in the rain. She prevailed on her husband to provide them with a chapel. This story does not seem consistent with the earlier construction of a chapel in Tamnavelton, which could presumably have been used by people from Richhill.

They are reputed to have honeymooned in Italy. On their return, Dolly's pity for Catholics taking mass in the open air leads to her husband providing land for a chapel.

William Richardson puts himself forward for election but almost immediately withdraws, realising he lacks the support required. In 1777 he is appointed High Sheriff of Armagh and in 1778 takes a commission in the Armagh Volunteers.

William Richardson beats the sitting MP, Thomas Dawson, and is elected member for Co. Armagh alongside Brownlow of Lurgan.

Dorothea died childless and was buried in the Richardson family vault at Kilmore Parish Church.

Louisa was a member of the prominent Waringstown family, the Magenisses, who had sent MPs to the parliament in Dublin and were related to the well-know philosopher, Bishop Berkley.

Inter-community friction between Catholics and Protestants in Co. Armagh grows throughout the 1780s and led to the establishment of secret gangs such as the Defenders (Catholics) and Peep-o-Day Boys (Protestant). A series of outrages by both sides led to open conflict at the Diamond in September 1795. Inhabitants of Richhill are said to have fought on both sides of this skirmish.
Following the battle, Catholics were driven out of Co Armagh, many fleetng to Co. Mayo.

Elizabeth Richardson is the eldest daughter of William and Louisa (nee Magennis). William and Louisa had married in 1794, when he was 45 and she was 21.

The Kingdoms of Ireland and Britain are united and the Irish Parliament is dissolved. William Richardson opposed the Union but was elected to the British House of Commons in 1807 where he served until ill-health forced him to retire in 1820.