Plate-fixed reference frames model how tectonic plates move relative to a global terrestrial reference frame such that the coordinates of points on the plate appear relatively stationary over time. By providing stability, localized, intraplate, and plate margin deformations are better detected in plate-fixed reference frames. Therefore, they offer significant advantages for quantification of many geophysical phenomena at national or regional scales, such as co/post-seismic deformation, glaciers mapping, and natural or anthropogenic hazards, along with geodetic and engineering applications that require long-term spatial stability, such as surveying and large-scale infrastructure monitoring. This session solicits contributions on determination and applications of national and regional reference frames and their associated challenges to improve their accuracy. Abstracts from analyses of geodetic techniques and their ties to ITRF2020 updates are particularly welcome. Papers on the crustal deformation modelling and exploiting the Intra-Frame Deformation Modelling (IFDM) aspects of the new reference frames are also strongly encouraged.