SR 40 begins at
SR 8 at the small community of
Woolwine. It heads northeast along the eastern side of the
Blue Ridge, crossing streams and foothills via a curving route. Around
Endicott, the highway starts to turn east, away from the ridge, and straightens out as the terrain becomes flatter. Between
Ferrum and
Rocky Mount, SR 40 parallels the
Norfolk Southern Railway's north–south
Winston-Salem District. The route intersects
U.S. Route 220 Business (US 220 Business) in downtown
Rocky Mount and the newer
US 220 bypass to the east, soon splitting from
SR 122, which leads northeast to
Bedford, and turning directly east. After it leaves
Rocky Mount, SR 40 heads east, largely along a newer alignment that utilizes
cuts and fills to provide a straight and level path. Approaching
Gretna, it intersects the
US 29 bypass, and then
US 29 Business in downtown
Gretna. This portion of the highway ends where it meets
US 501 at
North Halifax, turning north and crossing the
Roanoke River into
Brookneal.
US 501 and SR 40 split in downtown
Brookneal, with
US 501 heading northwest and SR 40 leaving to the northeast, but soon turning east. The highway passes through
Phenix on its way to
Charlotte Court House, where it intersects
SR 47 with a brief
overlap. Inside
Keysville, SR 40 meets the north end of
SR 59 and crosses
US 15/360 Business, and then crosses the
US 15/
US 360 bypass outside the town limits. Just beyond, the short
SR 385 provides access to
Southside Virginia Community College. SR 40 joins
SR 49 at
Lunenburg, overlapping that route to downtown
Victoria. From Victoria east to downtown
Kenbridge, where it meets the west and north ends of
SR 137 and
SR 138, SR 40 parallels the abandoned
Virginian Railway. The route leaves Kenbridge to the northeast, running past the north end of
SR 46 to a junction with
US 460 Business in downtown
Blackstone. After a short overlap with US 460 Business, SR 40 leaves to the east, while the business route continues northeast back to
US 460. Because SR 40 is south of US 460 Business on both sides of the overlap, SR 40 does not intersect US 460 here. Outside the town limits, SR 40 crosses through
Fort Barfoot. The route crosses
US 1 in
McKenney and
I-85 at exit 42 just to the east. After bypassing
Stony Creek to the south, SR 40 crosses
US 301 and
I-95 at exit 31; a short
State Route 40 Business follows the original route through Stony Creek, returning to SR 40 on the east end via a short overlap with US 301. Between
Sussex and a point east of
Homeville (where SR 40 crosses
SR 35), a secondary route to the south is the former alignment, now named Old Forty Road. Beyond Homeville, the last stretch of the highway heads northeasterly, crossing
US 460 in
Waverly before ending at
SR 10 at
Spring Grove.
State Route 646, a secondary highway, continues northeast beyond SR 10 to the former end of SR 40 in
Claremont. ==Major intersections==