States Admitted During Lincoln's Presidency: Zero

No new states were admitted to the Union during Abraham Lincoln's presidency (March 1861 – April 1865).

Context

• Pre-Lincoln: Kansas admitted January 1861 (Buchanan).
• During Civil War: West Virginia was created from Virginia (June 1863) and admitted as the 35th state—but this was a partition of an existing state, not a new territory becoming a state.
• Nevada was admitted October 1864—after Lincoln's re-election but before his second inauguration; technically during his first term. Correction: Nevada was admitted during Lincoln's presidency (Oct 31, 1864).

Correction

One state was admitted: Nevada (October 31, 1864). It was rushed to support Lincoln's re-election and the 13th Amendment. West Virginia (June 1863) was also admitted during his term.

So: Two states entered during Lincoln's presidency: West Virginia (1863) and Nevada (1864). The original answer was incorrect.