This study quantifies connectomic changes that occur within hippocampal subfields in patients with major depressive disorder (MDD). Using ultra-high field MRI (7 Tesla), we performed subfield-specific tractography in 6 MDD patients and 9 healthy controls. The degree of the hippocampal fissure was bilaterally increased in MDD patients compared to controls. Edgewise analyses revealed that CA3-vPFC, CA3-dlPFC, and CA1-vPFC edges were significantly increased in MDD patients compared to controls within the right hemisphere. These in vivo findings indicate that MDD patients display increased connectivity within certain hippocampal subfields, and between subfields the prefrontal cortex (PFC).