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Climatological features of the maximum electron density of the ionospheric F2 region (NmF2) are investigated and compared among the Arctic and Antarctic stations using long-term observations from the dynasonde measurements at Tromso, the EISCAT Svalbard Radar (ESR) measurements at Longyearbyen, and the digisonde DPS-4 measurements at Zhongshan, Antarctica. The NmF2 data are sorted as monthly medians of NmF2 for each hour, month, and solar activity. Results are presented as follows: (1) On the diurnal variability, the maximum value of NmF2 mainly occurs at local noon at the auroral latitude station Tromso, but at magnetic noon at the cusp latitude station Longyearbyen and between local noon and magnetic noon at Zhongshan, indicating the importance of soft particle precipitation and ionospheric convection in the cusp region. (2) In addition to the daytime peak, there is another peak just before magnetic midnight at Longyearbyen in winter during solar maximum years, which is attributed to the cross-polar transport of EUV ionization from day side to night side. (3) An enhancement of NmF2 is detected at magnetic midnight in winter at Tromso. It may be caused by the nighttime substorms. (4) On the seasonal variability, there are semi-annual anomaly at Tromso and normal variability at both Longyearbyen and Zhongshan during solar minimum years. (5) During solar maximum years there is always semi-annual anomaly for all three stations. The well-known winter anomaly is evident at both Tromso and Zhongshan, but does not exist at Longyearbyen. These anomalies are mainly due to the differences in photoionization and chemical compositions between the three stations. [ABSTRACT FROM AUTHOR]