Chronic hematomas are defined as hematomas with slow, progressive growth over many weeks. They are an extremely rare cause of acute neck swelling in the pediatric population. They consist of an organized central mass of blood with granulation tissue and fibrotic changes peripherally. The presence of a capsule prevents resorption but allows for intracapsular bleeding with subsequent expansion. We describe a case of a 6-year-old girl who presented to the emergency department with a spontaneously occurring left neck mass in the supraclavicular region. A possible neoplasm was suggested on imaging. The patient was referred to a head and neck surgeon, she underwent a thorough workup, and the mass was ultimately surgically excised. Histologically, the mass was confirmed to be a chronic hematoma. The patient recovered uneventfully, and there has been no recurrence.