The bus station is north of the center. If coming from the south, the journey, though indirect, will be a lot quicker if you route through Salvador or Feira de Santana. Real Expresso runs a few buses daily from Salvador (R$85, seven to eight hours). The same buses can be caught in Feira de Santana (R$63). Be sure to bring a sweater for the journey: these buses are notorious for blasting the air-conditioning.
Lençóis is 13km off Hwy BR-242, the main Salvador–Brasília route. There’s a gas station 22km east of Lençóis on Hwy BR-242, in Tanquinho. The drive from Salvador to Lencois takes about five to six hours.