Prior to that, it also continued south along N. Keystone Avenue to State Road 37 at Fall Creek Parkway, North Drive in Indianapolis.

Beginning at a junction with US 31 in Greenwood, SR 431 traveled along Madison Avenue northwest to the south side of Indianapolis.

The northern terminus of this section was at Madison's intersection with East Street, which formerly carried U.S. 31 from downtown to the south.

SR 431 was officially decommissioned on October 19, 2007,[citation needed] with the portions north of 96th Street being turned over to the city of Carmel.

[3] Carmel Mayor James Brainard immediately proposed banning heavy trucks from the route, the Hamilton County portion of which lies within his city's corporate limits.

Brainard also pushed for a plan to build six roundabout-style ("dogbone") interchanges on Keystone, built 2009–2010, in lieu of widening it to at least six travel lanes throughout.