Lancashire Constabulary conducted thousands of more stop and searches last year, figures show.
StopWatch UK said declining arrest rates across England and Wales suggest that relations between the police and the public are deteriorating.
Home Office data shows officers in Lancashire used stop and search powers 11,165 times in the year to March – up from 8,871 the year before.
The proportion of searches which led to an arrest did not change from 12 per cent over this period.
Across England and Wales, the number of stop and searches rose from 577,000 in 2019-20 to 704,000 in 2020-21.
This means almost 2,000 people were stopped per day on average last year, with figures peaking in mid-May 2020, when there were almost 3,000 searches each day.
But the national arrest rate fell from 13 per cent to 11 per cent – the lowest level since 2012-13.
Data for Greater Manchester Police is excluded from yearly comparisons because the force was unable to provide complete figures for 2019-20.
StopWatch UK said the vast majority of searches cause more problems than they solve.
Habib Kadiri, research and policy manager at the police monitoring organisation, said a fall in arrest rates reflects fears that police-community relations are backsliding.
The figures also show that across England and Wales, black people were significantly more likely to be searched than white people, though slightly less so than the year before.
In Lancashire, they were 4.2 times more likely to be stopped, compared to 3.8 in 2019-20.
Mr Kadiri added: “What is exceptional is how racial disparities persisted even during a global pandemic, proving that the police never stopped working tirelessly to overpolice people of colour.
“We simply would not accept this of any other emergency service profession. The police must do better.”
Across the two nations, 479,000 (68 per cent of all stops) were for drugs – the highest proportion since records began in 2006-07.
In Lancashire, 58 per cent of stop and searches were for this reason – up from 55 per cent in 2019-20, and also a record high.
Dr Laura Garius, policy lead for Release, which comprises experts on drug laws, said black and other ethnic minority individuals are being disproportionately targeted, despite drug use being no higher among these groups than among the white population.
She added: “The declining find and arrest rates are further proof that these powers are over-used, ineffective, and harmful to black and brown communities – in particular, black men – as well as those living in lower-income areas.”
The Home Office said police used extra officers and resources to tackle drug crime during the coronavirus lockdown, and also removed almost 16,000 dangerous weapons from our streets.
A spokesman added: “No one should be targeted for stop and search because of their race and there are extensive safeguards in place to prevent this.”