91st meridian may refer to:

• 91st meridian east, a line of longitude east of the Greenwich Meridian
• 91st meridian west, a line of longitude west of the Greenwich Meridian

• 91st Meridian, an electronic publication of the International Writing Program at the University of Iowa

• Superficial branches of transverse cervical arteries
• Superficial branches of ulnar nerves
• Superficial branch of the lateral plantar nerve
• Superficial branch of the medial circumflex femoral artery
• Superficial branch of the transverse cervical artery
• Superficial cerebral vein
• Superficial cervical fasciae
• Superficial cervical lymph node
• Superficial cervical nerve
• Superficial cervical nerves
• Superficial circumflex iliac arteries
• Superficial compassion
• Superficial dorsal vein of clitoris
• Superficial dorsal vein of penis
• Superficial dorsal vein of the clitoris
• Superficial dorsal veins of the clitoris
• Superficial empathy
• Superficial external pudendal arteries
• Superficial external pudic arteries
• Superficial fasciae
• Superficial femoral arteries
• Superficial fungal infection
• Superficial inguinal rings
• Superficial lateral cervical lymph node
• Superficial Love