Within the genus Pinguicula (Lentibulariaceae), 127 types of carnivorous plants have been detected, and Mexico has recently been regarded as a centre of such diversification. The Mexican Transition Zone (MTZ) comprises the main mountain ranges of Mexico, Guatemala, Honduras, El Salvador, and Nicaragua. The MTZ represents the boundary between the Nearctic and Neotropical regions, and its geodiversity and climatic complexity promote floristic richness, as well as angiosperm endemism, in Central and North America. Based on this, we expected that the species richness distribution and endemism of Pinguicula would show the same pattern. To prove this, the species richness distribution and endemism of Pinguicula in America were evaluated by country, ecoregion, biogeographic province, elevation gradient, and grid cell. For this, a database was constructed based on a review of herbaria specimens housed in electronic databases. Only records that include geolocation information and that have a voucher were taken into account. For the criteria of country, ecoregion, and biogeographic province, a count of the species within each polygon was carried out. Intervals of 500 meters were established for the elevation gradient criterion, whereas a cell size of 93 × 93 km was employed for the grid cell analyses. Pinguicula is distributed across 20 countries and Mexico harbours the highest number of species . The Pinguicula species grows in 104 ecoregions and is the richest in the Sierra Madre Oriental pine–oak forests. Meanwhile, 19 biogeographic provinces include almost one species, of which the Sierra Madre Oriental (SMO) province is the most diverse. On the other hand, richness based on the elevation gradient was concentrated between 0–499 and 1,000–1,499 meters. The grid cell analyses supported this, as they identified cells with significant richness and endemism within the MTZ in Mexico. The results showed that the pattern of species richness and endemism of Pinguicula was concentrated along the MTZ, particularly in the SMO.