The league is composed of one division. It has previous operated with multiple divisions. In the 1990s the league operated with three senior divisions, and a second tier division operated up until the 2016–17 season. Following on from this the league suffered from a lack of clubs, with only seven clubs completing the 2018–19 season, and ten, including two reserve sides making up the league for the 2019–20 season. For the 2020–21 season the league was not planned to function with eight of the league's teams instead being admitted to the Aberdare Valley League. The league returned for the 2021-22 season with a Premier Division of five clubs and a First Division of seven clubs. For the 2022-23 season, the league changed to just a Premier Division, sponsored by RTM Brickwork.
Member clubs 2024-25
The following clubs are competing in the Merthyr & District League during the 2024–25 season.[1]
Promotion from the Premier Division is possible to the South Wales Alliance League with the champion of the league playing the other Tier 7 champions from the South Wales regional leagues via play-off games to determine promotion.
^"Archived copy". www.merthyrtydfilafl.co.uk. Archived from the original on 29 January 2012. Retrieved 11 January 2022.{{cite web}}: CS1 maint: archived copy as title (link)