Indiana State Route 75 is the designation for two different north-south highways, on the west edge of what I'd consider "central Indiana". The northern segment begins at Indiana Route 218 in Camden, and runs south to US Route 421 in Frankfort. The southern segment begins at Indiana State Route 47 in Thorntown, just west of Interstate 65, and runs south to US Route 40 near Stilesville. The southern segment is longer. Both segments lie west of Indiana State Routes 29 and 39, but east of State Routes 55 and 59, so the number 75 is an anomaly on Indiana's highway numbering system.