This paper presents, for the first time, comprehensive measures of geographic accessibility to higher education both within and between the Republic of Ireland and Northern Ireland. Using geographic information system techniques, we find high levels of geographic accessibility to higher education in both jurisdictions. However, when we differentiate by type of higher education institution, we find that overall accessibility to universities in the Republic of Ireland is poor relative to Northern Ireland. Using data on enrolment and mobility rates, we find evidence that these geographic inequalities in accessibility may play a role in determining the type of higher education an individual pursues in the Republic of Ireland. Our analysis also explores the potential accessibility implications of recently announced changes to the structure of the higher education system in the Republic of Ireland. These changes are shown to result in an improvement in geographic accessibility to a university education in the south-west and south-east, with the north-west remaining at a disadvantage.