State-of-the-art astrogeodetic measurement systems—Digital Zenith Camera Systems (DZCSs) and the tachymeter-based QDaedalus systems—are currently used to obtain astrogeodetic deflection of the vertical (DoV) components. In this study, we use the CODIAC DZCS (accuracy ~0.05″) and two QDaedalus systems (accuracy ~0.20″) developed by ETH Zurich to collect DoV data in the Surses Region (Canton of Grisons), Switzerland. Based on these data, we assess the quality of the DoV predicted by the Global Gravity Model GGMplus and the Swiss Geoid model CHGeo2004. DoV data previously observed with the QDaedalus system in coastal (Istanbul) and smooth (Munich region) terrain areas were compared with GGMplus to determine the accuracy of the model for both types of terrain. The Surses Region was chosen for these observations because of its mountainous nature to examine the quality of the GGMplus model in mountainous terrain, as well as the GGMplus’ quality with the CHGeo2004. Astrogeodetic observations were conducted at 15 benchmarks in the astrogeodetic profile, at elevations ranging from 1185-1800 m and a station spacing of ~1.5 km. At one benchmark (BM12), observations were done with all three systems (eccentric BMs), while at 13 benchmarks, observations were only completed with the QDaedalus systems. Observations at the final benchmark were completed only with the CODIAC (0⁰ zenith angle) due to line of sight obstacles. The standard deviations of the QDaedalus data for each session are 0.04″-0.22″ and 0.01″-0.20″ for the N-S and E-W components, respectively. These high-quality data were compared to DoV data derived from GGMplus and CHGeo2004. The residuals from GGMplus are: The N-S component exhibit large residuals ranging from -2.31″ to 1.75″, while the E-W component residuals are -0.27″ to 1.80″. The residuals from CHGeo2004 range from -0.60 to 1.21 for the N-S components, and -1.01 to 0.32 for the E-W components. The results show that the predicted DoV data from CHGeo2004 are closer to the observed DoV, and more accurate than GGMplus. We conclude from these results that GGMplus is of significantly lower quality in mountainous terrain than in the smooth terrain of the Munich region (~0.2″, and reaching a maximum of 0.3″ and 0.4″ for the N-S and E-W components).