Marshall is a city in Kusilvak Census Area, Alaska, United States. At the 2010 census the population was 414, up from 349 in 2000. Currently…Marshall is a city in Kusilvak Census Area, Alaska, United States. At the 2010 census the population was 414, up from 349 in 2000. Currently, Marshall has reported a population of 492 from the most recent Census conducted in 2020.