somewhere north of the montgomery-treutlen county line, a second northbound lane forms along the left side of the existing northbound lane. the inner northbound lane becomes the primary lane as the outer-northbound lane ends just before the intersection with lawson beck road, only for a second southbound lane to form again north of mount olive church road until north of the intersection with sessions road. within soperton us 221/sr 56 gains the name mount vernon road, but north of fowler street and south third street, it curves to the right to intersect and become south second street. further in town, the routes have an intersection with srs 15/29 (west and east main streets) just before a railroad crossing. sr 15 briefly joins us 221/sr 56 from east main street for two blocks before turning left onto west louisiana avenue, where that route joins another concurrency with sr 78. at metter road, us 221/sr 56 intersects sr 46, then the name changes from north second street to swainsboro highway. the routes curve to the east-northeast, and just as it leaves the city limits runs along the northern edge of treutlen county airport (sr 46 runs along the southern edge), which is across from a small cemetery. the road remains at relatively the same trajectory, until it intersects sr 86, then curves towards the north-northeast just before crossing interstate 16, at exit 78. north of there is the rural community of gillis springs where sr 56 turns east to leave the concurrency with us 221 and a new concurrency along georgia state route 171 begins.