A 65-year-old man with a history of a left-sided inguinal hernia presented with three days of left-sided groin pain worsened with exertion and fatigue. The patient was afebrile but tachycardic, and physical examination revealed a tender, erythematous immobile bulge in his left groin. Laboratory studies revealed leukocytosis. Lymphadenopathy secondary to infectious or inflammatory etiology was suspected. However, point-of-care ultrasound (POCUS) identified extensive deep vein thrombosis (DVT) of the lower left limb. Follow-up imaging revealed this to be secondary to May-Thurner syndrome, a mechanical compression of an iliocaval vein against the lumbar vertebrae by a common iliac artery. This report demonstrates how POCUS can be used to identify lower extremity DVT, thereby expediting diagnosis and treatment and potentially preventing complications.