Rock Creek Island State Preserve

Rock Creek Island is a 30-acre wooded island in the Cedar River in Cedar County. It is located 0.5 mile upstream from the town of Rochester and has been owned by the state of Iowa since Iowa became a state in 1849.

About the Land

The island was dedicated as a geological state preserve in 1983.

There are only a few large, relatively stable islands on interior streams in Iowa. The mouth of Rock Creek drains into the Cedar River just to the east of the preserve, hence the name. 

This island is more than a half-mile long and 500 feet wide, and demonstrates long-term alluvial dynamics. The upstream end of the island, its oldest and highest part (ten to fifteen feet above normal river level), gradually erodes while new material is continually added to the younger, lower end (three to five feet above normal river level). 

Directions

1. The preserve is an island in the Cedar River. It is not accessible by land. 
2. From the intersection of I-80 and Highway 1 on the north side of Iowa City, go east on I-80 for 13 miles to County Road X40 (exit 259). 
3. Turn north (left) on County Road X40 (Garfield Avenue) and go 4 miles to Cedar Valley Park in the town of Cedar Valley. 
4. From the boat ramp there, you may float 5 miles downstream to the preserve, an island in the Cedar River. 
5. Downstream from the preserve about 1 mile, there is a boat ramp at Rochester Park near County Road F44, south of the town of Rochester.

Plants

Silver maple and hackberry are the dominant tree species over most of the island, accompanied by a variety of trees including: 

• Sycamore
• Bitternut hickory
• Walnut