SR 231 begins in Humphreys County in downtown McEwen at an intersection with US 70/SR 1. It heads north as Main Street to pass through neighborhoods before leaving McEwen and passing northwest through farmland for several miles as Erin Road. The highway then crosses over a wooded ridge just before crossing over White Oak Creek and entering Houston County.  SR 231 then winds its way northwest as McEwen Road to cross another ridge before traveling up a narrow valley, where comes to an end at an intersection with SR 13 just south of Erin. The entire route of SR 231 is a two-lane Highway and lies entirely atop the Highland Rim.