Alexander White Baldwin (June 1835 – November 14, 1869) was a United States federal judge.
Baldwin read law, was admitted to the Bar at the age of 19, was in private practice in Virginia City, Nevada from 1858 to 1859. He was a prosecuting attorney for Storey County, Nevada in 1859, returning to private practice by 1865.
On March 10, 1865, Baldwin, then 29 years of age, was nominated by President Abraham Lincoln to a new seat on the United States District Court for the District of Nevada created by 13 Stat. 440. He was confirmed by the United States Senate on March 11, 1865, and received his commission the same day. Baldwin served until his death in a railroad accident in Alameda, California.
His father, Joseph G. Baldwin, was also an attorney who served as an Associate Justice of the California Supreme Court.