| Specimen ID | 116303 |
| Group | Mollusks-Bivalves |
| Genus | Dreissena |
| Species | polymorpha |
| Common Name | zebra mussel |
| State | IL |
| County | Cook |
| Locality | Chicago River (R.M. 322.5) at Mason's Slip |
| Mapping Accuracy | Accurate |
| HUC8 Name | Chicago |
| HUC8 Number | 07120003 |
| HUC10 Name | North Branch Chicago River-Chicago Sanitary and Ship Canal |
| HUC10 Number | 0712000301 |
| HUC12 Name | South Branch Chicago River-Chicago Sanitary and Ship Canal |
| HUC12 Number | 071200030107 |
| Map | |
| Collection Day | 29 |
| Collection Month | 10 |
| Collection Year | 1991 |
| Year Accuracy | Actual |
| Potential Pathway | hitch hiker on small watercraft |
| Status | established |
| Record Type | Personal communication |
| Freshwater/Marine | Freshwater |
| Number Collected | 140/sq.m |
| Year Class | juvenile |
