| Business | Phone |
| Lyon County Assessor 206 S 2nd Ave, Rock Rapids 51246 | (712) 472-3592 |
| Lyon County Auditor 206 S 2nd Ave, Rock Rapids 51246 | (712) 472-3713 |
| Lyon County Treasurer 206 S 2nd Ave, Rock Rapids 51246 | (712) 472-3703 |
| Tax Office 206 S 2nd Ave, Rock Rapids 51246 | (712) 472-3704 |