Cooke Castle is rich in history

Had it not been for Jay Cooke’s savvy banking skills, the Union might not have had the money it needed to successfully fight the Civil War and ultimately reunite the country. 

Cooke, a Sandusky native who owned his own banking house, came up with the idea of selling war bonds and worked with Secretary of the Treasury Salmon Chase to help the Union obtain loans from Northern banks. 

These efforts allowed the Union to keep its soldiers supplied with what they needed to fight the war and keep getting their paychecks. 

In addition to the North’s success, Cooke also became a very wealthy man. He was also a deeply religious man, and he wanted to build a summer home in a peaceful place where he and his family could enjoy nature and take time for prayer and solitude. 

Outside Cooke Castle stands a historic marker, as well as a monarch butterfly station. Some of the butterflies that OSU has studied there have been found in Mexico after their long migration.He settled on Gibraltar Island, a 6.5-acre rock just across the harbor from South Bass Island and its village of Put-in-Bay. He bought the island for $3,001, says Chris Winslow, director of Ohio Sea Grant at Ohio State University, which today owns Gibraltar Island.

In 1864, Cooke began building his large summer home, known as Cooke Castle, from limestone quarried from the Lake Erie Islands.  

The turret, which is visible above Gibraltar Island’s trees and one of the first landmarks visitors to Put-in-Bay see when the Jet Express ferry turns into the harbor. The castle has three levels, and the turret is a fourth. 

At the castle, Cooke, his family, and their guests relaxed and enjoyed the island lifestyle of boating, fishing and even afternoon naps. They sometimes would take a boat over to nearby Green Island and explore. 

Cooke regularly invited members of the clergy to the island to recharge and reconnect with their spirituality while enjoying the island and surrounding natural areas. 

Other guests included Civil War hero Gen. William Tecumseh Sherman and President Rutherford and First Lady Lucy Hayes. Cooke and the first lady often enjoyed fishing around the islands.

Today, the castle is part of Ohio Sea Grant’s Stone Lab on Gibraltar Island. In the years after the Cooke family sold the island to Ohio State, Cooke Castle has served different purposes, including as a men’s dormitory for Stone Lab students and housing a telescope on the roof. 

Ohio State has maintained the integrity of the structure and has an endowment to keep it in sound shape. Since 1998, the university has replaced the roof, repaired windows using authentic period glass from France, restored the mortar and reconstructed the porches. 

Original decorative molding and plastwork is still intact inside Cooke Castle, which was built in 1864 and 1865.“The university loves the fact that we own that castle,” Winslow says. “We work hard to keep it in the condition it is in.”

Inside, the first-floor rooms are empty but still maintain touches that Jay Cooke put in for his special retreat. 

The library’s original built-in wood bookshelves, which held Cooke’s favorite books and likely his Bible, are in excellent shape and remain unchanged since Cooke’s day.
Decorative molding above the light fixtures and original woodwork around the door and windows show the home’s Victorian past, and the decorative fireplaces remain intact. 

Interpretive panels that Ohio State put in are located around the first floor, shedding light on the life the Cooke family and their guests enjoyed there. 

The upstairs is closed off and is not in good enough shape to hold visitors. 

At this time, there are no plans for any interior work. Although the university knows the historical importance of the castle, it is focusing on Stone Lab’s mission of research, education, and outreach. 

Gibraltar Island is a private island, but visitors can tour it during public tours of Stone Lab on certain days during the summer months. The interior of Cooke’s Castle is not part of the tour, but visitors can see the exterior. For tour details, visit