Hartford is a city in Lyon County, Kansas, United States. As of the 2010 census, the city population was 371. It is part of the Emporia Micropolitan Statistical Area.
Hartford is located at 38°18′28″N 95°57′23″W / 38.30778°N 95.95639°W / 38.30778; -95.95639 (38.307866, -95.956313). According to the United States Census Bureau, the city has a total area of 0.4 square miles (1.0 km²), all of it land.
As of the census of 2000, there were 500 people, 200 households, and 125 families residing in the city. The population density was 1,329.1 people per square mile (508.0/km²). There were 220 housing units at an average density of 584.8 per square mile (223.5/km²). The racial makeup of the city was 98.20% White, 0.60% African American, 0.40% Native American, 0.60% from other races, and 0.20% from two or more races. Hispanic or Latino of any race were 0.40% of the population.