Office for National Statistics figures recorded the lowest proportion of smokers in the UK to date, with e-cigarettes playing a "major role" in the decline.
The ONS data shows 10.3% of people aged over 18 in Monmouthshire were smokers in 2021, up from 8% the year before. It was also a fall from 13% five years ago.
Last year, a further 27.1% of adults in the area were ex-smokers while 62.6% had never smoked.
Women in Monmouthshire smoked more than men with 8.1% taking up cigarettes, while 12.7% of men smoked.
Hazel Cheeseman, deputy chief executive of Action on Smoking and Health, welcomed the overall fall in smoking levels, but said the Government must not become "complacent".
Ms Cheeseman added that without a new tobacco plan from the Government, "the vision of being smoke free by 2030" will not be met.
The current tobacco control plan aims to reduce smoking prevalence among adults in England to 12% or less by the end of 2022.
Nationally, 14.1% of adults in Wales were smokers with those aged from 45 to 54 (18.3%) making up the highest proportion of smokers.
Across the UK, 13.3% of adults smoked cigarettes in 2021, down from 14.0% last year and a significant fall from 20.2% a decade ago.
The ONS said the increase in people taking up e-cigarettes has played a "major role" in the fall with a separate survey finding 7.7% of those aged 16 and over in Great Britain last year used an e-cigarette daily or occasionally.
It was an increase from 2020, when 6.2% of people reported daily or occasional e-cigarette use.
The survey found that the proportion of vapers was highest among current cigarette smokers (24.6%) and ex-cigarette smokers (14.8%), with only 1.7% of people who have never smoked reporting that they vaped.
David Fothergill, chairman of the Local Government Association’s community wellbeing board, said that councils can help deliver the ambition of eliminating smoking in England by 2030, but needed certainty over long-term funding.
Mr Fothergill added: “Reducing smoking rates among the remaining 5.4 million smokers in England is the single biggest thing we can do to improve the nation’s health."