||Human capital is indispensable for regional innovation and economic growth, and PhD graduates (PhDs) play an important role in these processes. This is the first study describing the geographic origin and current work location of PhDs from Dutch universities, which are located in a densely populated area with a high concentration of basic science and science-based industries. Our study shows that their country of origin is strongly related to the field of study, as engineering PhDs were born outside The Netherlands much more often than PhDs from other fields. Furthermore, we show that PhDs disproportionally come from the same region as where the PhD university is located. PhDs also frequently did their pre-PhD degree at the university where they obtained their PhD degree. Finally, a disproportionate number of PhDs stay in the PhD region to work, especially if they also did their pre-PhD degrees at the PhD university. The extent of PhDs staying in the PhD region varies by sector, with PhDs in the higher education sector staying in the PhD region more often than PhDs working in other sectors. This implies that the geographic concentration of PhDs in the region of the PhD university is mainly due to PhDs staying to work at the same university rather than employment opportunities in other (science-based) industries—a finding at odds with Dutch science policy, which promotes mobility in academia but also stresses the importance of the region in innovation by science-based industries.