The data for Marshall County are summarized in this water planning data fact sheet.
Marshall County is located in central Iowa.
Manufacturing is the principal economic sector, as measured by employee earnings. The county contains gently rolling hills, the Iowa River Valley, and small drainage streams. The population of 38,276 is distributed in 13 incorporated cities and the surrounding rural areas. State Highway 14 crosses the county from north to south. U.S. Highway 30 crosses the county from east to west.