Title: Cohomology of Fuchsian groups and non-Euclidean crystallographic groups Author: Sam Hughes Affiliation: University of Southampton Abstract: For each geometrically finite non-Euclidean crystallographic group (NEC group), we compute the cohomology groups. In the case where the group is a Fuchsian group, we also determine the ring structure of the cohomology. Finally, we compute the $L^2$-Betti numbers of the NEC groups.