Which states ratified the Sixteenth Amendment after 1913 and when did they do so?
Executive summary
The Sixteenth Amendment’s formal ratification process reached the requisite three-fourths threshold in early February 1913, and Secretary of State Philander C. Knox later certified the amendment that month; several state legislatures continued to record their ratifications after February 3, 1913, adding a short tail of approvals through March 1913 [1] [2] [3]. Dissenting claims that the amendment was never validly ratified have been litigated and repeatedly rejected in federal courts and official histories [4] [5].
1. How the ratification countdown worked — and why dates differ
Congress proposed the income-tax amendment in 1909 and required ratification by the legislatures of three-fourths of the states — 36 of the 48 states then in the Union — for it to become effective; ratification was completed when the thirty-sixth legislature approved, and the Secretary of State later proclaimed certification [1] [3]. Contemporary records mark February 3, 1913, as the date when the thirty-sixth state approved the amendment (Delaware, Wyoming, and New Mexico are all recorded as approving on February 3), but the Secretary of State’s formal certification came later in February, on February 25, 1913 [2] [6] [3]. That gap explains why some sources list February 3 as the completion date while others emphasize the February 25 proclamation [2] [3].
2. The brief list of states that ratified after February 3, 1913 — specific dates
A small group of state legislatures recorded ratifications after February 3, 1913: New Jersey ratified on February 4, 1913; Vermont ratified on February 19, 1913; Massachusetts ratified on March 4, 1913; and New Hampshire ratified on March 7, 1913 [1]. Those later approvals arrived after the practical three‑fourths threshold had already been met but are part of the official roll of ratifications collected by Congress and archivists [1] [3]. West Virginia’s ratification on January 31, 1913, preceded the February 3 cluster and so is not part of the “after 1913” tail, while many other states had approved earlier in 1911–1912 (examples include Wisconsin and New York in 1911; Arizona and Minnesota in 1912) [1].
3. Why some modern disputes over ratification exist — and how courts and scholars have treated them
A minority of writers have argued the Sixteenth Amendment was never properly ratified, with books like The Law That Never Was claiming procedural defects; those claims have been litigated and rejected, and courts have upheld the amendment’s validity while official government histories and the National Archives recognize its ratification and subsequent certification in 1913 [4] [5] [3]. The contested arguments typically pick at documentary technicalities — for example, which states sent formal instruments of ratification and when — but the authoritative record used by the Secretary of State and later federal certifying bodies treated the amendment as ratified when the required number of state legislatures had approved [4] [3].
4. Bottom line and archival authority
The practical bottom line is twofold: three‑fourths of states had approved the Sixteenth Amendment by February 3, 1913 (with Delaware, Wyoming, and New Mexico among those approving that day), and several additional states formally ratified in the weeks that followed — specifically New Jersey (Feb. 4, 1913), Vermont (Feb. 19, 1913), Massachusetts (Mar. 4, 1913), and New Hampshire (Mar. 7, 1913) — before the Secretary of State’s February 25, 1913 certification and the amendment’s acceptance into the Constitution [1] [2] [3]. Official repositories including the National Archives, the Library of Congress/Constitution Annotated, and historical summaries in the House archives provide the documentary trail for those dates [3] [1] [6].