Graphene Nanoribbons (GNRs) are quasi-onedimensional materials based on carbon. They can be synthesized from suitable molecular precursors under ultra-high vacuum conditions. Thanks to this approach, it is possible to create GNRs with a width and edge-structure defined to the last atom. Their length, however, is statistically distributed and influenced by the parameters of on-surface synthesis. Importantly, it is a key parameter for their integration into functional electronic circuits that would allow to characterize their novel properties. In this publication we show how Raman spectroscopy can be used to characterize the length of GNRs and investigate the interaction with their environment.