Venous aneurysms are rare causes of neck mass. Among neck veins, aneurysms of the external jugular vein are extremely uncommon. We present a case of a woman with a history of prior internal jugular vein catheterization who presented at a rural primary health care unit with a nontender progressively enlarging swelling in the right supraclavicular region. B-mode and Doppler ultrasound examination revealed a saccular dilatation of the external jugular vein, suggesting a posttraumatic venous aneurysm. Saccular aneurysms of the external jugular vein are uncommon and only rarely lead to serious complications. Access to ultrasound examination can allow early detection of this entity.