Delahay, Mark W., jurist and politician, was a native of Talbot county, Md. Although his father was a slaveholder, his maternal ancestors were members of the Society of Friends, and he was averse to buying and selling slaves. He had scarcely attained to his majority when he decided to seek his fortune in the West. He first located in Illinois, where he was engaged in various enterprises; wrote for different journals; studied law, and was admitted to the bar. In 1853 he went to Mobile, Ala., to practice law, but in the winter of 1854 he became interested in Kansas, and in March, 1855, became a resident of Leavenworth. Although a Democrat and a supporter of the policy of "squatter sovereignty," his sympathies soon became enlisted with the free-state cause. On July 7, 1855, he began the publication of the Leavenworth Register. He served as one of the secretaries of the Topeka convention of Sept. 19, 1855, and as a member of the Topeka constitutional convention the following month. In December, while he was attending the free-state convention at Lawrence, his office was destroyed by a pro-slavery mob. He was elected to Congress under the Topeka constitution but was never admitted to a seat. In May, 1857, he started the Register, the first paper in Wyandotte (now Kansas City), Kan. He was a member of the Osawatomie convention of May 18, 1859, which founded the Republican party in Kansas; was chief clerk of the house of representatives in 1860; was appointed surveyor-general of Kansas in 1861 and held the position until Oct. 7, 1863, when President Lincoln appointed him United States district judge of Kansas, in which office he served until 1873. He died at Kansas City, May 8, 1879.