Natural beaches are narrow on the west side of Lake Michigan, as a littoral current is constantly carrying the sand from north to south. But if you construct a groin extending perpendicular to shore, sand will begin to collect on its north side.

In the 19th century, though, the lakefront was thought of largely as a location for industry and shipping—not swimming. Large homes and resort hotels were located to exploit its cool breezes, but it appears that recreation was primarily boating or sitting near the water. Undoubtedly boys went swimming in various locations, but a broad bathing beach doesn't seem to have been desired or created until early in the 20th century. The first ones were created at Diversey, at Wilson, and at 63rd; the two on the North Side were subsumed by later landfill projects.

Extensive landfill projects of the 1910s-1920s created nearly all of Chicago's lakefront parkland, including its bathing beaches. Since the new beaches were far out from the original shore, they would have dropped off into 40-foot-deep water, so artificial bottoms had to be built for the swimming areas. The sand is held by a series of groins. Even so, the Chicago Park District moves beach sand a hundred feet inland into windrows every fall before winter storms arrive. In the spring, they replenish the sand with material trucked (or barged) over from Indiana.