Boulders at Katy Trail Apartments for rent in St. Charles, MO, has luxury 1, 2 and 3 bedroom garden-style apartments for rent. Just minutes from St. Louis County. This 2006 Property of the Year is in close proximity to Hwy 364, I-270 and I-70 in the AAA rated Francis Howell School District. Unbeatable amenities include: outdoor pool w/water jet massage & waterfalls, mountain bikes available to ride Katy Trail and detached garages & carports. Call us today, because when it comes to complete resident satisfaction, no one delivers more.