Vermillion is a city in Marshall County, Kansas, United States. As of the 2010 census, the city population was 112.
Vermillion is located at 39°43′8″N 96°15′55″W / 39.71889°N 96.26528°W / 39.71889; -96.26528 (39.718860, -96.265214). According to the United States Census Bureau, the city has a total area of 0.2 square miles (0.6 km²), all of it land.
As of the census of 2000, there were 107 people, 56 households, and 31 families residing in the city. The population density was 422.3 people per square mile (165.3/km²). There were 82 housing units at an average density of 323.6 per square mile (126.6/km²). The racial makeup of the city was 99.07% White and 0.93% Native American. Hispanic or Latino of any race were 5.61% of the population.