Since its construction in 1856, the Stockdale Mill has produced flour and corn meal, but the dam that powers its turbine also blocked upstream fish migration in the Eel River. Because nearly 80% of freshwater riverine fish species are migratory and depend on connected stream habitat for spawning, rearing, and overwintering, barriers such as dams and culverts can harm fish populations, yet migratory freshwater fishes in Midwest streams have been less studied than coastal diadromous species. In 2013, after the Stockdale Mill Foundation approved the project, a four-year effort began to install a prototype fish ladder so fish could safely cross the dam, complete their life cycle, and genetically connect populations above and below it. Biologists had studied Eel River fish populations and the effects of barriers on migration for many years, and the Stockdale Mill dam was chosen as a representative site to test a one-of-a-kind fish passageway invented by B.K. Riverfish, LLC. After two years of laboratory research and development, a full-scale prototype was constructed and delivered to the Stockdale site on August 14, 2017, an antenna system to track fish movement in the river and ladder was installed in September 2017, and the ladder officially opened in mid-November 2017. Since then, more than 15 fish species have been observed in the ladder, fish as small as three inches have moved through it and around the dam, and fish as large as two feet are expected to be able to swim up it, making this the first time in 160 years that fish could pass around the dam. The ladder will continue to be monitored to evaluate how many and what kinds of fish use it, while the project highlights both the problem of barriers to migratory freshwater fish and an innovative way to let fish pass dams while preserving the history of the site and similar historic places.