A Spigelian hernia is a very rare hernia, making up approximately 0.1% of all abdominal wall hernias. This hernia goes through a defect in the Spigelian fascia which is the part of the transversus abdominis aponeurosis lateral to the rectus muscle, often at the level of the arcuate line, where the fascia is widest and weakest. We present the case of a 77-year-old female with no past surgical history who presented to our teaching hospital with high-grade small bowel obstruction secondary to an incarcerated Spigelian hernia. She was taken to the operating room for a laparotomy and a portion of the small bowel mesentery was found to be strangulated. The hernia was reduced, and the defect was repaired primarily. The diagnosis of a Spigelian hernia can often be difficult to diagnose on history and physical examination alone, but computed tomography (CT) imaging can be a valuable adjunct in diagnosis. Prompt surgical treatment should ensue when the diagnosis of high-grade bowel obstruction is made in a patient with imaging findings consistent with a Spigelian hernia.