There were nearly 1,300 drug seizures in Irish prisons last year.
According to Freedom of Information figures, the highest amounts were in three jails in Dublin.
Across this region, Castlerea had at least 30 drug seizures.
In 2020, there were 1,251 drug seizures in 10 jails across the state.
By far the highest amount was in Wheatfield Prison in Dublin, which has over 500 male inmates.
There were 479 drug seizures in this jail last year, with the next highest being 319 in the men's section of Mountjoy prison.
Another jail in the capital city, called Cloverhill, was the third highest, at 207.
There were 116 drug seizures in Limerick prison last year, with Castlerea, Cork, and Midlands jails all having at least 30.
The total amount of seizures across all jails was exactly the same in 2020 as in 2019.