The police recorded 84.2 crimes per 1,000 people a year in Mountain Ash from September 2023 to August 2026, 10% higher than the typical town's 76.2. The most common was violence and sexual offences, at 47.7. In the 12 months to August 2026 it was 85.5, up from 81.4 in the 12 months to August 2024.