-> How the BBC's Gentleman Jack sparked global awe of Yorkshire rebel Anne Lister and Shibden HallThe broadcaster said the figure equated to nearly a quarter (24.1 per cent) share of the audience – the highest overnight figure since episode one.
However consolidated figures will be higher, and likely to be in the region of six million viewers, a spokeswoman said.
The final episode of the eight-part series went out to audiences on Sunday night.
It comes after it was revealed that 600,000 viewers in Yorkshire and Lincolnshire had been watching the series, which first aired on HBO in the USA.
The show follows the story of Halifax land owner Anne Lister (Suranne Jones) and her relationship with Ann Walker (Sophie Rundle).
Speaking previously, West Yorkshire-born writer and executive producer Sally Wainwright said: "I am delighted that so many people across the region have been enjoying the show.
"I hope they're all as thrilled as I am that this bold, brilliant, life-affirming daughter of Halifax is now being celebrated - as she deserves to be - on a global stage."
-> Thanks Jack...Gentleman Jack drama brings tourism boom – The Yorkshire Post saysMiss Lister wrote a detailed diary of her daily life and left behind twenty-six volumes of 7,722 pages, of an estimated five million words. The diaries give a great insight into her life as a landowner, businesswoman, intrepid traveller, mountaineer and lesbian, according to Calderdale Museums.
Since Gentleman Jack began airing on BBC One and on HBO in America, Calderdale Council has reported an increase in tourism in the region, with visitor numbers to Shibden Hall, the home of Anne Lister, increasing from roughly 150 on a good day to 300-400, according to museums manager Richard Macfarlane.