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.