Mobile phone location datasets offer opportunities to conduct spatial analysis at very granular levels. In most jurisdictions their collection and use are subject to legal requirements to protect the privacy of the individuals generating the data and to prevent its disclosure. However, it can be the case that geographically referenced datasets, which meet the legal and statistical requirements of non-disclosure, reveal much more when they are plotted on a map. This paper provides an overview of the particular ethical challenges posed to mapmakers by mobile phone location data, whilst keeping in mind the potential benefits of harnessing these data to inform research and public policy. We identify the principal ethical concern pertaining to the use of such location datasets: preventing disclosure and protecting privacy, but also considering the spatial and socio-political contexts that the data are collected and produced from. We then discuss case studies that highlight the context-specific considerations necessary to create ethical maps from sensitive location datasets, and offer experience-based recommendations for users considering the ethical implications of using mobile phone location data in research.