This paper offers an in-depth analysis of the characteristics of innovative start-up firms in Trentino, a high-income mountainous area in the North East of Italy. This work is part of a series of thematic papers on regional start-up landscapes in Italy, produced by the OECD Trento Centre for Local Development. Following the 2018 OECD Evaluation of the Italian Start-up Act, which embraced a national perspective, it represents a first attempt to analyse the impact of this policy at the local level. Among Italian regions, Trentino boasts the highest density of registered innovative start-ups over all young firms established locally. However, innovative start-ups spread unevenly throughout this territory, concentrating in urban areas. Female and young founders are less prevalent than in Italy at large. Firm dynamism, in particular high-growth and exit trends, the uptake of emerging technologies among local start-ups as well as their propensity to use national incentives are other key areas of this work, which concludes with a set of evidence-based recommendations for policy makers.