Investigating the range and population dynamics of introduced species provides insight into species behavior, habitat preferences, and potential of becoming established. Here, we show the current population status of the red-necked wallaby (Notamacropus rufogriseus) in Britain based on records from an eleven-year period (2008–2018). Records were obtained from Local Environmental Records Centres (LERCs), the National Biodiversity Network (NBN), and popular media. All records were mapped and compared to a historical distribution map (1940–2007), derived from published data. A total of 95 confirmed wallaby sightings were recorded between 2008 and 2018, of which 64 came from media sources, 18 from Local Environmental Records Centres (LERCs), seven from the National Biodiversity Network (NBN), and six from the published literature (Yalden, Br. Wildl., 24, 2013, 169). The greatest density of wallaby sightings was in southern England, with the Chiltern Hills Area of Outstanding Natural Beauty a particular hot spot (n = 11). More sightings were recorded in August than in any other month. Much of the species’ ecology and responses to British biota and anthropogenic pressures are unknown, and therefore, further research is warranted. The methods used here are widely applicable to other non-native species, particularly those that the public are more likely to report and could be an important supplement to existing studies of conservation and management relevance.