Despite skirting the Gainesville City Limits, SR 331 runs north and south as a four-lane divided rural highway.

Like the segment that's part of SR 121, it runs southeast and northwest until it curves directly west and east before approaching U.S. Route 441 (US 441; Southwest 13th Street).

After passing through some lowlands leading to Bivens Arm Lake, the former SR 329 takes the name of South Main Street away, and SR 331 runs exclusively along Southwest Williston Road.

The two routes cross the Gainesville-Hawthorne State Trail before finally turn directly north and south in the Lincoln Estates neighborhood.

[2] At some point the route was truncated to its current location in Gainesville.