Shellsburg is a city in Benton County, Iowa, United States. The population was 938 at the 2000 census. It is part of the Cedar Rapids Metropolitan Statistical Area.
Shellsburg is located at 42°5′35″N 91°52′13″W / 42.09306°N 91.87028°W / 42.09306; -91.87028 (42.093058, -91.870272).
According to the United States Census Bureau, the city has a total area of 0.7 square miles (1.9 km²), all of it land.