Population of Morgantown, WV. Last official estimated population of Morgantown city (Monongalia County**, West Virginia state) was 31,073 (year 2014) [1]. This was 0.01% of total US population and 1.68% of total West Virginia state population. Area of Morgantown city is 10.4 miÂ² (=27 kmÂ²) [6], in this year population density was 2,979.19 p/miÂ². If population growth rate would be same as in period 2010-2014 (+1.17%/yr), Morgantown city population in 2018 would be 32,553*.