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Visual Obstruction Reading (VOR) is a nondestructive method used to determine the height and density of vegetation on rangelands and commonly used by United States Forest Service (USFS) to assess vegetative structure of wildlife habitat. In this study, three ecological sites (loamy, thin loamy, and claypan) were assessed to determine if they were biologically capable of producing high structure (VOR greater than 8.89cm, or 3.5in) at the end of the grazing season (October). Two study locations were established on the McKenzie (LMNG) and Grand River (GRNG) Ranger Districts of the USFS Dakota Prairie Grasslands. Each location had 24 – 60m x 60m exclosures, eight within each ecological site. The VOR was recorded within each exclosure every 10m along a 200m transect in the summer and fall of 2012, 2013 and 2014; with mean VOR calculated for each site. Phytomass was collected every 20m using a 0.178m2 hoop, then dried and weighed. Afterwards, mean VOR and standing crop weights were tested for correlation using a linear regression model. Mean VOR surpassed the 8.89 cm threshold in the fall of 2012 and 2013 on the loamy sites at LMNG, while the thin loamy and claypan sites did not achieve the high structure threshold. At the GRNG, the mean VOR surpassed the high structure threshold only on the claypan sites in 2013. In conclusion, only the loamy ecological site on the LMNG achieved high structure when assessing the mean levels; however, all ecological sites had the potential when assessing the VOR range within each ecological site. Although only the claypan ecological site achieved a mean VOR ranking of high structure on the GRNG in 2013, all ecological sites had a VOR range that achieved high structure. Weather conditions did impact VORs during the study, with dry conditions and heavy snow lowering mean VORs.