Spencer is a city in McCook County, South Dakota, United States.

[8] On May 30, 1998, the most destructive and second deadliest tornado in South Dakota history struck Spencer.

Continuing toward the east-southeast, it struck several farmsteads before crossing the Hanson/McCook County line a half mile west-northwest of Spencer.

At this time, the tornado was being observed by the OU Doppler on Wheels crew, whose mobile Doppler weather radar data showed up to 264 mph winds in the tornado a few tens of meters above ground level.

[9] The population of the town diminished soon after to less than half of what it was previous to the tornado, from 315 to 145 in April 1999, and has since hovered around that mark.

According to the United States Census Bureau, the city has a total area of 0.27 square miles (0.70 km2), all land.

The racial makeup of the city was 96.8% White, 0.6% African American, and 2.6% from two or more races.