The route covers a portion of Bridge Street in the city of Yerington.

SR 340 begins at the intersection of Bridge Street and State Route 339 just west of the city limits and east of Yerington Mine.

From there, the highway heads east on Bridge Street, immediately crossing over the Walker River.

The route passes through farm areas and just north of the Yerington Paiute Indian Colony as it heads into more populated areas of the city.

SR 340 travels a little over 1 mile (1.6 km) on Bridge Street before the designation ends at the junction of Main Street (State Route 208).