Since 2003, the intervention unit of Santé publique France in the Provence-Alpes-Côte d'Azur and Corsica region has been conducting a descriptive study of thyroid cancer cases and has investigated whether there is a higher incidence of this disease in Corsica. The study included patients residing in Corsica between 1998 and 2011 who underwent surgery for thyroid cancer in Corsica or on the mainland during that period. Case identification was conducted in the healthcare facilities that treated the patients and identified using data available in the national database of the Medical Information System (PMSI). This research was supplemented with data on long-term illness (ALD) designations for thyroid cancer managed by health insurance funds. Case validation was performed after reviewing the medical records of patients who underwent surgery. From 1998 to 2011, 587 new cases of thyroid cancer were identified among residents of Corsica, with a female-to-male ratio of 2.5. The highest number of cases was observed among women aged 40 to 59 and among men aged 50 to 59. The tumors were predominantly papillary microcarcinomas. Among women, the incidence of thyroid cancer in Corsica per 100,000 person-years was 15.9 [14.3–17.5] for the period 1998–2011. This estimated incidence was twice as high in Southern Corsica as in Northern Corsica, with this difference widening between 1998 and 2011. Among men over the same period, the incidence of thyroid cancer in Corsica per 100,000 person-years was 6.4 [5.4–7.5]. The difference by department of residence was also observed among men, but it was smaller and not statistically significant. The situation in Corsica regarding thyroid cancer in terms of incidence and clinical characteristics is similar to that of other French departments located both in the west and east of mainland France. The increase in the incidence of thyroid cancers in Corsica, particularly papillary thyroid cancer, is likely linked to an increase in diagnoses among a population that is particularly aware of this issue. However, we cannot rule out the possibility that there is also a genuine increase in incidence linked to lifestyle, the environment, or genetic abnormalities.