- Ophion obscuratus is widely distributed across the Palaearctic (Europe and temperate Asia).
- The apparent range of O. obscuratus may have been counfounded with those of similar species (records from Argentina, for example, are certainly erroneous). Nevertheless, this is certainly a widespread and frequently abundant species.
- Across Britain, O. obscuratus is one of the most frequently trapped nocturnal ichneumonids. It can be found in a variety of habitats and is particularly abundant in gardens.