Stephen Arnold Douglas (born April 23, 1813) was a Democratic senator from Illinois who served in the United States Senate from December 4, 1843, until December 31, 1861. Representing Illinois at large rather than a specific district, he held the office of senator for five terms, marking a lengthy and influential tenure in national politics. His service in the Senate places him among the notable historical members of Congress from Illinois in the mid-nineteenth century.

During his years in office, Douglas was identified with the Democratic Party and was consistently returned to the Senate as a leading figure from his state. Although specific committee assignments, offices, and contact details are not recorded in the available metadata, his long service from 1843 to 1861 underscores his sustained role in federal legislative affairs. By the end of his Senate career, he was recognized as a former senator, having concluded an 18-year span in the upper chamber of Congress.