Once the bounty of Lake Betsie was discovered, a number of "easterners” began buying land around the lake. With harbor improvements key to the area’s growth, private interests undertook the first harbor improvement in 1859, spending $16,000 to dredge a channel between two short piers at the river mouth.

Soon, Frankfort became the most northerly improved harbor on the eastern shore of Lake Michigan. With vessels making the Manitou Passage less than five miles offshore, the harbor soon became an ideal and frequently used harbor of refuge.

Concurring with the growing importance of the harbor, Congress dispatched the Army Corps of Engineers to Frankfort to begin improvements on July 1, 1867. Plans for the new harbor called for the cutting of a new channel approximately seven hundred and fifty feet to the south of the natural outlet. This opening was then to be dredged to a width of two hundred feet and an overall depth of twelve feet. Protected by a pair of parallel piers and revetments, Lake Betsie would thus be opened-up to the largest vessels of the day.

With the Corps of Engineers returning to undertake continued improvements in the harbor, the South Pier was lengthened an additional 200 feet in 1884. While the work was underway, a violent storm swept through the area, and waves crashing across the pier destroyed 90 feet of the elevated walkway, and severely damaged an additional 170 feet.