This paper uses statistical analyses to understand the effect of proximity of old prisons on property prices. The study employed semilog hedonic regression models: a quantitative research method applied to assess the impact of proximity to heritage gaols on property prices for a case study of HM Prison Pentridge in the time range between 2015 and 2019. Results demonstrated that the former Pentridge has a variable effect on properties lying in and around its current heritage borders. Pentridge shows a diminution effect on prices of residential properties on its land currently being developed to a mixed-use precinct, as well as its intimate surrounding residences. Inversely, Pentridge shows a positive price effect on properties lying at distances between 400 m and the maximum study range of 1400 m in the case of ‘houses’ and between 600 m and the range of 1000 m in the case of ‘units.’ Findings of this research suggest that prices of properties with direct visual access to Pentridge’s structures are negatively affected. Results also suggest that Pentridge’s current redevelopment project may have contributed positively to property prices lying outside the direct visibility zone. To be able to further validate these interpretations, similar research may consider other variables influencing property valuation, such as direct visibility of the gaol as well as interviews that assess the ‘attractability’ of Pentridge’s redevelopment. Future studies may examine the rate of change in property price along time for each distance band from the gaol borders. Future research may also consider duplicating the methodology to assess the comfortability towards gaols converted to museums, as well as gaols that are still in operation. The originality of this research emerges from the distinct lack of quantitative evidence in the current literature. Most research has investigated uncomfortable heritage focusing on qualitative assessments of memory, stigma, commemoration, and shame, with limited scholarly attention paid towards property depreciation effects as a result of Australia’s prison history, nor increasing effects due to gaols’ reuse and redevelopment. Decision-makers and stakeholders of equivalent dark heritage reuse projects will find this research useful in understanding potential impacts on surrounding property prices. Property valuers and real estate companies operating in Coburg—a suburb of Melbourne, Australia—may use the related tables and figures in guiding their business for the coming years.