Maryland Route 115 is a Maryland state highway that goes from MD 124 in Washington Grove to MD 655 in Norbeck. The entire route is in Montgomery County.

Maryland Route 115 begins its eastward trek at the divided MD 124 and bears southeast along Muncaster Mill Road along a four-lane, divided alignment. Quickly the road condenses into two lanes and weaves through a short patch of forest with a residential area to the south of it. Crossing Shady Grove Drive, a large divided road, the road passes through Redland and passes through a suburban residential development. Beyond this and exiting the wooded area, it passes by a school and turns south, and then east again into another largely wooded area fronted with homes, coming to an intersection at MD 28 in Norbeck. It continues just beyond this intersection to MD 655, where it ends officially at the old alignment of MD 28, appropriately named "Old MD 28".

The entire route is in Montgomery County.