Formoso is a city in Jewell County, Kansas, United States.

[5] According to the United States Census Bureau, the city has a total area of 0.28 square miles (0.73 km2), all land.

[6] The 2020 United States census counted 94 people, 43 households, and 22 families in Formoso.

There were 52 housing units at an average density of 210.5 per square mile (81.3/km2).

41.9% of households consisted of individuals and 25.6% had someone living alone who was 65 years of age or older.

There were 65 housing units at an average density of 232.1 per square mile (89.6/km2).

41.7% of all households were made up of individuals, and 20.8% had someone living alone who was 65 years of age or older.

45.6% of all households were made up of individuals, and 29.4% had someone living alone who was 65 years of age or older.

There were 6.9% of families and 11.6% of the population living below the poverty line, including no under eighteens and 18.8% of those over 64.

The community is served by Rock Hills USD 107 public school district.