Places beginning with SI in Iowa, United States
- Siam
- Sibley
- Sibyl (historical)
- Sidney
- Sidney, Township of
- Sigourney
- Sigourney, Township of
- Silver City
- Silver Creek Mobile Home Community
- Silver Creek, Township of
- Silver Creek, Township of
- Silver Creek, Township of
- Silver Lake
- Silver Lake, Township of
- Silver Lake, Township of
- Silver Lake, Township of
- Silver, Township of
- Sinclair
- Sioux Center
- Sioux City
- Sioux City
- Sioux County
- Sioux Rapids
- Sioux Rapids, City of
- Sioux, Township of
- Sioux, Township of
- Sioux, Township of
- Sioux, Township of
- Sioux, Township of
- Sixmile
- Sixteen