The Longford Westmeath area has the highest number of heroin users in the Shannonside region.
Just over 260 people have presented for heroin addiction in the Longford Westmeath Local Health Office district this year.
Roscommon has 20 users seeking opioid dependence therapy, while the Sligo Leitrim area has the lowest at just under 17.
In all three local health office regions the number of men is nearly double that of women seeking help for addiction.
The number of patients seeking treatment this year has fallen since last year in all three regions.