Grainfield is a city in northern Gove County, Kansas, United States. As of the 2020 census, the population of the city was 322. Grainfield had it…Grainfield is a city in northern Gove County, Kansas, United States. As of the 2020 census, the population of the city was 322. Grainfield had its start in the year 1879 by the building of the railroad through that territory. It was named for the wheat fields in the vicinity.