One of the things that made the road possible was a treaty the state of Indiana forged with the Pottawatomie on October 16, 1826. Governor James B. Ray led the negotiations. It allowed for a ribbon of land 100 feet wide to stretch from the Ohio River (at Madison) to Lake Michigan (Michigan City). The Pottawatomie left the region by the very road when the last of their tribe was forcibly removed in the 1838 Pottawatomie Trail of Death.
A commission was selected to route the road from Indianapolis to Lake Michigan in 1828. It was told to make the trailhead be the best harbor, preferably natural, that could be had with Lake Michigan. The Kankakee River's swamp posed a problem for the construction of the road, forcing the commission to avoid a more direct northwesterly route and instead have it go from Logansport, Indiana straight up to the south bend of the St Joseph River (now South Bend, Indiana), and then west to Lake Michigan. Michigan City was formally selected to be the trail end in 1832.
The route from Madison to Indianapolis was straighter. From Madison it went north through Ripley and Jefferson counties straight to Napoleon, Indiana, and from there straight through Shelby County, Indiana to Indianapolis.
It proved to be the preferred route to Indianapolis for 34 separate counties, even through the road only went through 14 counties. In 1836 the Indiana General Assembly passed the Mammoth Internal Improvement Act, the act provided funds to pave the entire length of the road. However, the economic difficulties brought on by overspending and the Panic of 1837 caused the state to enter partial bankruptcy before the entire length could be paved. The situation forced Indiana to give control of the road to the individual counties as part of a plan to avoid losing it to the state's creditors.
State Road 29, originally much longer, followed the route from Madison to Bryantsburg, and from Napoleon in the south to Logansport in the north. State Road 25 followed the original route to Rochester, Indiana. U.S. Route 31 followed the original route from Rochester to South Bend, Indiana. State Road 2 and U.S. Route 20 follow the original road from South Bend to Michigan City.
The later U.S. Route 421 replaced Indiana State Road 29 from Madison to near Boyleston; the original route for US 421 was altered when Interstate 465 was constructed. A more truck friendly route was also built from Madison to North Madison. (The section of US 421 from Bryantsburg to Napoleon through Versailles was originally made SR 29 to conform with the law creating the state highway system in 1919.)
The original US 31 has been bypassed in several locations, most notably, in terms of the Michigan Road, from Rochester to north of Plymouth, Indiana. SR 29 from the south into Logansport has been decommissioned, as has the entire route (that which remains) from north of Greensburg (JCT I-74/US 421) to the northwest side of Indianapolis (JCT I-465/US 421).
In Indianapolis, a few remnants of the road still remain. A tollhouse stands just north of the White River. It was erected by the Augusta Gravel Road Company to recoup its costs in repairing the road. It was built about 1850, as a simple one-story frame building. It was raised to two stories in 1886. The building operated as a toll house from about 1866 to 1892. The building was also used as a post office, notary public office, and general store.