The counter station is located at the weir in Sion Mills. It is a partial counting site as it only has 2 channels spanning 6m of a possible 162m.
Below is the Net Up count for Sion Mills Counter on the River Mourne from 2012 to 2022
| Year | Net Up Count |
|---|---|
| 2012 | 2836 |
| 2013 | 3162 |
| 2014 | 3852 |
| 2015 | 1824 |
| 2016 | 1350 |
| 2017 | 912 |
| 2018 | 1214 |
| 2019 | 2824 |
| 2020 | 3915 |
| 2021 | 3197 |
| 2022 | 1371 |
Location of Counter
Site Details - Partial Count
| 1 | Width of River at weir during high flow | 162m |
| 2 | Attraction Weirs No Array | 15m |
| 3 | Breadth of Channels/Arrays: | 6m |
| a. Channel 1 | 1m | |
| b. Channel 2 | 5m | |
| 4 | Electrode Total Length: | 26 |
| 5 | Width Not Covered by Array | 156m |
| 6 | Logie Installation | Sep-96 |
| 7 | Operational Start Date 2100C | May-97 |
| 8 | First Data Set | Jun-97 |
| 9 | Camera | 2 x Arial |
| 10 | Camera Coverage | Area Only |
| 11 | Required Salmon Upstream every year | 8000 Management Target |