Williamsburg is a city in Franklin County, Kansas, United States. As of the 2010 census, the city population was 397.
Williamsburg is located at 38°28′48″N 95°27′58″W / 38.48°N 95.46611°W / 38.48; -95.46611 (38.480115, -95.466016). According to the United States Census Bureau, the city has a total area of 0.3 square miles (0.9 km²), all of it land.
As of the census of 2000, there were 351 people, 139 households, and 98 families residing in the city. The population density was 1,036.0 people per square mile (398.6/km²). There were 161 housing units at an average density of 475.2 per square mile (182.8/km²). The racial makeup of the city was 97.15% White, 1.71% Native American, and 1.14% from two or more races. Hispanic or Latino of any race were 0.57% of the population.