Kirwin is a city in Phillips County, Kansas, United States. As of the 2010 census, the city population was 171.
Kirwin is located at 39°40′19″N 99°7′19″W / 39.67194°N 99.12194°W / 39.67194; -99.12194 (39.672052, -99.121931). According to the United States Census Bureau, the city has a total area of 1.0 square miles (2.5 km²), of which, 0.9 square miles (2.5 km²) of it is land and 0.04 square miles (0.1 km²) of it (3.06%) is water.
As of the census of 2000, there were 229 people, 96 households, and 60 families residing in the city. The population density was 241.5 people per square mile (93.1/km²). There were 151 housing units at an average density of 159.2 per square mile (61.4/km²). The racial makeup of the city was 96.94% White, 0.87% African American and 2.18% Native American. Hispanic or Latino of any race were 2.18% of the population.