Vermillion is a city in Marshall County, Kansas, United States.

The racial makeup of the city was 94.6% White, 1.8% Native American, and 3.6% from two or more races.

35.2% of all households were made up of individuals, and 13% had someone living alone who was 65 years of age or older.

41.1% of all households were made up of individuals, and 26.8% had someone living alone who was 65 years of age or older.

There were 8.0% of families and 9.9% of the population living below the poverty line, including 10.0% of under eighteens and 9.8% of those over 64.

The community and nearby rural areas are served by Vermillion USD 380 public school district.