[3] St. Charles Rock Road/Route 180 proceeds northwest past several cemeteries, crosses under I-170 within St. John, then continues through Breckenridge Hills and St. Ann.

A path between the two came to be known as King’s Highway, a name used in colonial times by the Spanish and then the French for many frequently used roads.

From Wellston to the current location of Lindbergh Boulevard the line ran in a straight shot while the road meandered around St. John and Breckenridge Hills.

When the interurban line stopped running in the 1930s, the Road Rock was reconstructed on the railroad right-of-way for a direct shot into St. Charles.

Today, a portion of the streetcar right-of-way, complete with poles, has survived intact on the south side of the Rock Road just east of Earth City Expressway.