As surgical extended total extraperitoneal (eTEP) access for simple and complex procedures becomes widespread and more sophisticated, an expanded understanding of the organization and intricacy of the various extraperitoneal spaces is required. Immediately superficial to the peritoneum throughout is an adherent layer known as the extraperitoneal fascia. Between the extraperitoneal fascia and the layers associated with the myofascial (parietal) components of the abdominal wall, there are predictable patterns of fat distribution within multiple defined areas of the extraperitoneal space. This chapter will examine the four clinically meaningful access regions of the extraperitoneal space: the central ventral region, the suprapubic region, the subxiphoid region, and the flank/lumbar region. Each of these four extraperitoneal regions has at least one landmark fascial layer or complex which subdivides the local space into separate, distinct, and surgically important extraperitoneal compartments. Understanding in which compartment to dissect, and how to best connect and transition between these distinct components of the extraperitoneal space, is a fundamental concept to both minimizing surgical complications and consistently maximizing ideal patient outcomes.