[1] In East Baton Rouge Parish, the highway is named Greenwell Springs Road.

From the southwest, LA 37 begins just west of a cloverleaf interchange with US 61/US 190 in the city of Baton Rouge.

The highway heads northeast along Greenwell Springs Road and, about a mile after exiting the city limits, curves northward.

Now running parallel with the Amite River, LA 37 begins a concurrency with LA 64 that lasts through much of Central, a newer city that encompasses smaller communities such as Greenwell Springs.

After a short distance, LA 37 leaves the river's path and heads northeast through rural St. Helena Parish to its terminus at LA 10 in Greensburg.